Hopeful,
No wise words of wisdom here. I don't know how old your son is.
My son was 28 (approx.) when he last got clean - but had struggled with a couple attempts before that. He was homeless at the time and ended up in a recovery house and then sober living on the governments expense. (They were NOT top of the line places.)
I remember the googling and searching I used to do to try to find a place for him . . . I was doing waaay more work searching than he ever was. I was torn apart thinking of my son being cold, hungry, lonely, on the streets, etc. For us, it wasn't until I had reach the end of my rope of helping him, turned my back on him, that he finally took responsibility of himself.
Sorry, I'm not much help, but your post just reminded me of what I went through. Good luck and I hope your son finds what he needs.