Society. The very notion of "well" etc (and most things we believe to be "good" or "ethical") comes from shared culture, else it's totally arbitrary personal preference.

It's not about "logical objective reasoning" either. Treating people bad for example. Nothing "logical" about it being more wrong that treating them nice (especially if it benefits you to do so). But the culture we co-created and live in makes it wrong (and that's a good thing).

Society has been trending towards "arbitrary personal preference" in many areas lately. Conversely, society has condoned and even encouraged things that are horribly unfair. So I don't see why we would carve out an exception for judging the "well-lived-ness" of a person's life based on society's precepts about the number or closeness of friends and family.

>Society has been trending towards "arbitrary personal preference" in many areas lately

Yeah, or degenerating, one could say. It also happened in the last days of Rome...

>Conversely, society has condoned and even encouraged things that are horribly unfair.

Well, it's a balancing act. Society doesn't mean people get a free pass to abandon personal judgement. That said, all those "horribly unfair" things seem horribly unfair to us, from a distance. To their own society they looked perfectly normal.

Somehow I don't think that's what anyone is doing here.