theres basically two options:
make them wards of the state and stick them in an institution.
or
create a city for homeless people, similar to china's kowloon city.
https://en.wikipedia.org/wiki/Kowloon_Walled_Citythe best would probably give them the option to choose. either they can go live on their own in t he city, or they live in the institution and abide by strict rules. break the rules and they move you to the city.