Want a simple explanation that sense restraint is an important aspect of ethical conduct, for a loved one who is not into Dhamma

There can come a time for any one of us who are indulging our desire for pleasure (such as desire for attractive and entertaining eye candy, liking to listen to music and wanting to smell nice odors, looking to delight your taste buds with comfy places to lie on and lost in thoughts etc. etc. ) the thought of what is it like walking to the beat of a different drummer. Then a thought would cross ones mind, what would it be like to practice Buddhism? One has to first learn to take baby steps. You know well that it is impossible to jump over the wall of a big fortress. One can only enter through the door. Similarly, one cannot jump over walls to enter the dispensation of the Supreme Buddha. It can be entered only through that one door. That door is called, “listening to advice.” Once a person learns to take delight in advice that door opens immediately.

However, that advice he receives may be gentle and sweet at times and bitter and rough at other times. Every so often those words of advice may even feel like whiplashes. But the person who likes advice does not assess the nature of advice. He happily accepts it, knowing that it is for his benefit.

If one begins this journey through ethical conduct, that can be a big leap into this road less travelled. Note that ethical conduct is one of the three main lines of development of the noble eightfold path. “The avoidance of all wrongdoing, The undertaking of what is skillful, The cleansing of one’s own mind—This is the teaching of the buddhas.— Dhammapada 183.

All of us afraid of going to have to let go of our sensual pleasures. As the Buddha said, the reason we’re afraid of death too is because we’re afraid we’re going to have to let go of our sensual pleasures. If you look into the mind to see it’s doing, to see where you’re adding any unnecessary element of stress, you will see the other side of indulging in sensual pleasures. The Buddha located that unnecessary element in craving, and specifically in three types of craving. The first is craving for sensuality, and here sensuality doesn’t necessarily mean sensual pleasures. The Buddha makes the point that our intentions for sensuality are what we’re really attached to. The idea of sensual pleasure, the activity of thinking about sensuality, is a lot more attractive than the actual pleasure itself.

You can obsess about the idea over and over and over again, whereas the actual pleasure, once you’ve experienced it, quickly grows stale and is gone. Then you have to find another one to replace it. But ordinarily we don’t get so upset about replacing it because then the new pleasure provides more fodder for our sensual obsessions, and as long as we can keep on obsessing, we feel we’re okay.So our craving for sensuality, this tendency of the mind to keep obsessing about, planning about, how it’s going to experience different sensual pleasures: That’s what we’re really attached to. We really cling to that, feed on that. It’s our fodder. So that’s the first kind of craving.

Lets take the life of a Buddhist Monk. He is one who observes the eight precepts, and thereby move into another area of training for the mind. The eight precepts add the element of restraint of the senses. Each of the added precepts places restraints on the types of pleasures we might try to get through the sense doors. The precept against illicit sex turns into a precept against sex, period. That covers all of the sense doors right there. Then there’s the precept against eating after noon or before dawn. That covers pleasures of taste. The precept against watching shows, listening to music, using perfumes and scents covers pleasures of sight, hearing, and smell. And then the precept against high and luxurious beds and seats covers the sense of touch. As you go down the list, you can see that each of the five senses is covered. This adds a higher level of restraint and places some barriers on our typical ways of indulging our desire for pleasure: evening munchies; the desire for a nice, thick mattress to lie on; wanting to smell nice; liking to listen to music.

By taking on these precepts, you learn to put some barriers around your self-indulgence. These barriers serve several purposes. One, they focus you on the meditation: If you’re going to find any pleasure in the course of the day, you have to look more intently at developing pleasure in the meditation to make up for the restrictions you’ve placed on your foraging for pleasure outside. In addition, you learn important lessons about indulgence. If you tend to be indulgent in your daily life, you’re going to be very self-indulgent when you meditate. If you can’t say No to your daily desires, it’s going to be hard to say No to them while you’re sitting here mediating. The mind-states that want to go off and think about pleasant sights, sounds, smells, tastes, and tactile sensations are very easy to indulge in if you don’t have the habit of saying No to your impulse to look for pleasure in those things throughout the day. As you develop this habit of saying No to sensual indulgence in the course of the day, it’s a lot easier to say No to sensual thoughts in the course of the mediation.

You’ve also developed the habit of learning when to say “enough,” which will hold you in good stead as you begin to develop the sense of non-sensual pleasure and rapture that come with concentration. You’ll be more likely to realize when you’ve indulged enough in those kinds of pleasure so that you can turn to the further work you need to do in terms of insight and discernment. You can’t just stay wallowing in the pleasure of concentration. You’ve got to learn how to understand what’s going on in the mind, why it creates mental worlds to begin with—the worlds that pull you away from the present moment and lead to suffering and stress.

So the precepts are a crucial part of meditation. They help you develop good habits and foster insight. In particular, they help you see into your habits of self-indulgence. A lot of the pleasures we indulge in really do get in the way of deeper pleasure, deeper happiness. We all want to have our cake and eat it too.

When we play chess, we want to keep all our pieces and yet win at the same time. But an important lesson in life is that certain pleasures really do get in the way of higher happiness. You’ve got to learn how to say No to them. And to develop a sense of moderation: how much pleasure is enough for you to do the real work at hand. Ultimately, you see that even the most harmless pleasures in this world are not absolutely harmless. This realization leads to the sense of samvega that motivates you to look for an even higher pleasure: the absolutely blameless bliss of nibbana.

So learn to look at the precepts as an important part of the meditation. They’re not Sunday school rules or “conventional truths” that someone who hits the more “ultimate truths” can eventually put aside and discard with impunity. They’re an important part of training the mind in the skills and attitudes it’ll need in concentration, in developing discernment, and ultimately leading to release. So how you meditate in daily life is by being very careful about your precepts, respecting them, and being alive to the lessons they teach.

The simile of the Six Animals in SN 35.206 might be useful...

Saddha leads to Seela. So try to bring him to an understanding that:

1. There is no real refuge from kama vastu (money, wealth, parents, spouses, children, looks, education, government, etc.)
2. True refuge is the Buddha; his Teachings; and the Sangha who led by example.
3. Only a well guarded mind can bring one's own happiness and peace
4. Enlightened ones explain the workings of the mind
5. Impurity of mind manifest in speech n conduct
6. By default an impure mind is unable to be at peace... and enjoy worldy blessing .... let alone see the Truth of samsara

Personally I try presenting the Buddha's views as an "alternative knowledge" to common knowledge of modern man. I tell my children that a Buddha's knowledge is far superior -- it's based on Dana, Bala, Jnana (generosity, strength, knowledge) -- whereas what modern fields of knowledge says is that it's based on sensory perception of the 5 sense faculties

I also help to practice Seela (precepts):

1. By example, as far as possible
2. Pointing out the exemplary conducts in real life... jataka stories where the bodhisatwa practised the virtues under extremely difficult conditions... also buddhist stories of lives of Disciples.... and any family or friends who are keeping precepts
3. Inculcating values such as, "all living beings are equal... all are in samsara, with a mind and a body that is liable to experience pain... thinking of oneself, one does not harm other living beings"

Right view means understanding the four noble truths.

Right intention follows as a consequence of right view.

There are three intentions (renunciation, non-aversion or loving-kindness, and non-injury or compassion).

And what is right resolve? Being resolved on renunciation, on freedom from ill-will, on harmlessness: This is called right resolve. (SN 45.8)

Right view gives motivation to renounce attachment (clinging to pleasure, fame, and so on ... these are usually seen as desirable but with right view you see that they lead to dukkha ... with right view you naturally choose to renounce them).

I'm not sure whether that's an important aspect of ethical conduct, though ... according to many definitions of "ethical", it's the intentions of loving-kindness and compassion, not the intention of renunciation, that motivates ethical conduct.

Still, I suspect they develop together (the factors of the eightfold path are inter-related).

It may be possible to think of examples of where someone has hurt or ignored another, either because they're busy greedily chasing a sense-pleasure or because they're suffering the consequences of misplaced attachment -- for that reason even if "ethical" is taken to mean "good to others", renunciation (to avoid attachment and suffering) is "an important aspect" (which, for example, may make it easier to follow the precepts).