Upvote:2
Depends of the size of the population and their memory of their previous life.
Small groups usually are democratic or they have a weak leader, while bigger groups might be more like a chiefdom, which is a basic form of goverment in primitive human societies.
While bigger the population is in a reduced space, more complex the goverment will be.
But, in other side, these people will have memory of their former goverments. Hence, if there are enough survivors, they could restore their former kind of goverment. That's what usually happens after a band of nomads attacks a sedentary population, a plague reduces drastically the population or a war kills most part of population, after the shock, the sedentary population restores their former organization if possible (sometimes some reforms appear later).
Hence, probably both you and your friend are correct, it's just an issue of population and territorial size what kind of goverment will develop, probably passing through many stages:
band of hunter-gatherers -> chiefdom -> feudalism, kingdom or theocracy -> etc