I think you're doing just find with this, Lake, and it sounds like your son is doing fine too.
We moms would like to thing that there really IS a safe place for our addict kids, a place where there will be no drugs and no problems and where they will be safe and clean.
Sadly, there is no safe place with addiction. Many stay clean in terrible neighbourhoods and under poor conditions, and some cannot stay clean if you put them on a desert island 1000 miles from the nearest dealer...it just works like that.
I think your son will be fine. And he will be fine or not fine regardless of where he lives.
Hugs