Boy, have I ever been where you are. Only, I am fortunate to have TWO sons like this!
The oldest is the least troublesome, but he did get out of jail about 2 months ago. I told him he could stay with me 30 days drug free. But, he HAD to get into a halfway house. He immediately got a job. He's done well. And last week he got into a halfway house. He doesn't like it, but that's too darn bad. He's a good kid at heart, but got mixed up with drugs and ruined his life. Now he has to pay. It hurts me, but pushing him to take care of his own self is the best thing I can do for us both.
I hope things don't get out of control for you. I just find that having an active addict in the house only brings torment, chaos and unending grief. I deal with it much better from a distance.