How to show compassion for attention-seeker

There would be no need to show it, but how ever:

Much karuṇā toward good householder suffering so much.

metta & mudita

:-)

Got it? Or to practical, to much at the essence?

Help your self out first, since if not abound sense pleasure, there is less to help and meanwhile compassion is contained in simply not harming, meaning be very serious in the precepts. That is highest and real compassion, right resolve.

[Note that this hasn't been given for stacks, exchange, other worldbinding trades, but for a tool to escape from this wheel of "compassion"]

Loud harshness is the voice of suffering. The Buddha spoke with quiet kindness:

DN30:2.24.2: “He never spoke a loud harsh word, insulting, quarrelsome, causing harm, rude, crushing the people.

One might avoid loudness, but that might be cruel. It might be kinder to listen with equanimity. That listening may ease your friend's suffering somewhat.

That "hole" you mention is the desire to be heard. Desire is the root of suffering. With this in mind, the most direct response is to listen quietly, with equanimity.

And if one is pressed afterwards with, "So what do YOU think?". One might answer truthfully, "I think you feel upset about X". Acknowledged, your friend will feel heard and subsequent discussion will be quieter. This will require, however, practicing equanimity. And that practice will be of value, since there is an underlying tendency towards avoidance here.

Loud speech is often divisive. So one must be very very careful here. It takes skill to exercise love, compassion, rejoicing and equanimity to bridge such divisiveness. If the skill has not yet developed, one might say, "I am sorry that I lack the love, compassion, rejoicing and equanimity to solve X. I cannot help you."

Be a good friend as you can and keep company with other good friends.

SN45.3:1.3: “Sir, good friends, companions, and associates are the whole of the spiritual life.”

Might not be the easiest or most pleasant exercise but advice the Buddha gives in SN 15:11 could be of use at some of the times:

... When you see someone who has fallen on hard times, overwhelmed with hard times, you should conclude: ‘We, too, have experienced just this sort of thing in the course of that long, long time.' [transmigration] ...

Try imagining yourself being clueless in exactly that sort of way and others around not finding a way of telling you about it going for advice to one another asking "how can feel compassion for that person instead of being aggravated?" You, on a rare but periodic occasion spot a thought in your mind that "people are asking advice one another on how to feel compassion for me" but find no way to stop continuing being the same way (hard times in the mind). It's a strech of imagination, but if worked through gradually - might give a release to the mind for a while. Then, try other methods before doing this sort of reflection again.

Ah, the story of the Bengali Tea Boy:

When the great Buddhist teacher Atisha went to Tibet [...] he was told the people of Tibet were very good-natured, earthy, flexible, and open; he decided they wouldn’t be irritating enough to push his buttons. So he brought along with him a mean-tempered, ornery Bengali tea boy. He felt that was the only way he could stay awake. The Tibetans like to tell the story that, when he got to Tibet, he realized that he need not have brought his tea boy: the people there were not as pleasant as he had been told -- Chödrön, Pema, "Start Where you Are" (1994) 83–84

Being loud is an expression of life: a way of experiencing one's own existence in the reflection of others. It's a bit like screaming 'Hello!" off a cliff, and thinking that the echo that comes back is the mountains acknowledging you. Being quiet is a different expression of life: a way of experiencing one's own existence directly, internally. And note that it's not quite as clean-cut as it sounds; I've known people who meditate in an extremely loud, self-directed manner, and others who are thoroughly outgoing with a quiet, self-knowing grace.

Suggest to your friend that s'he sit with you, so that s'he can grapple with the vicissitudes of quietness. And remember that it isn't h'er loudness that disturbs you, but the loudness s'he triggers inside of you. Grapple with your own disquiet, and no outer noise can disturb you.

I have had similar experiences of both - being the observer (the quiet one) and the performer (the loud one) - neither is wrong. However, what a wonderful opportunity to practice compassion 😊