This is a long time since you posted. Never, ever, ever doubt yourself and your need for safety. Let your son go, quietly ask him to go and change the locks on back and front door.
Only HE can get himself sober and clean. Nothing we do, nor say, helps when addiction takes over. You deserve a much better and calm life. At his age, you shouldn’t be worrying so STOP worrying and take care of you first each and every day. It’s not selfish, it’s life-saving.
Perhaps read Melody Beattie’s book “Codependent no more.”
My younger brother never made it out of drug misuse. He lived 30 miles from us and I saw him every 2-3 months. I gave up expecting him to change when he was in his early 20s. He took his life at 54. Very sad. There were some happy years, but mostly unhappy. We CAN’T change them, it has to come from within. Sending hugs…