I've had several friends who, through no fault of their own I could find,
were kicked out of there houses or made clear that they were not welcome.
A few of them actually left on their own because people at their homes (very
rarely a biological parent or sibling) made it an unhealthy enviornment.
Each of these friends though, found someone close to them whose family was
willing to take them in. At younger ages parents will take friends in (depending
on the family and circumstance) but almost everyone has someone they can
rely on whose parents want to protect you.
At an older age, a few of my friends asked their friends parents for a place to
be safe in exchange for chores or a small rent (like $40/mo of their work pay)
and so they had a home they could come to, while they were working out things
with their folks.
That may not work for everyone, but never be too proud to ask, it may suprise you
who in your friend group as an open couch and an open heart.
Older people who live with family may consider moving to a relatives house to "help"
I didn't want to move back in with my parents after the economy went south so I
moved in with my grandmother and am her help and her watch since she lives alone
and on her own. Its a good compromise and it has helped me build a better relationship
with my parents. (not great but better)