Welcome eveningprimrose,
I also let my daughter come home after rehab. She had her relapses. It wasn't easy and I wish she would have gone to a sober living house. But that was in the past. Today she is sober and doing pretty well. She still lives with me and it is not a perfect situation but I am thankful that she is sober. I know you want to do whatever you can to help him to stay on track. I would do the same. Ultimately it is his choice no matter where he lives to stay sober. When I think back of all of the things I did to help her to stay sober.....I wonder just how many of those things were a waste of my time and effort. It was really all up to her.
I wish you and your son the best. There is a lot of support here.....come back.
Hugs............Lo