Why do parents allow their adult children to be homeless?

Hey, I am not from the West (Kenyan). I therefore find it quite difficult to understand why parents allow their children to be homeless.

To be specific, I am looking at America. There are loads of homeless people who have parents. Why are they so insensitive to their offspring? I do understand if their children are "Headaches" it would make sense, but I have watched many documentaries of homeless people and loads are just ordinary people who have fallen on bad times or luck (At least it seems).

Are Western parents this un-empathetic? They seem like people who only care about their children till they are eighteen. From there it's not their concern.

EDIT: I apologise for the generalisations. But this is what it looks like.

  1. POV of Kenya: https://www.youtube.com/watch?v=J-ojnQJpUGo&t=121s (Kenya is more developed than you think)

  2. For people who got kicked out and/or homeless for no fault on their own, we would like to apologise for that and wish you healing from all that trauma plus good times ahead.