God..it kills me to read this. I know what you are feeling...wish I didn't, but I do ;(
I don't know that I could have stayed out of it at the beginning of my 'awakening' to my son's drug use. Not even if I did know what I do now. I think we have to at least try...it comes after trying and failing that we fully accept we can't control it. But I do know as a parent we have to try... we just do.
I remember when I would hear of my son's peers and the horrible stories of how drugs had taken them over. Sometimes to death. I would say to him "Thank GOD you never got into that stuff (Heroin). He would look me in the eye without a blink. I just never knew what was going on right under my nose...and they are good at hiding it, for a while.
Geeze, I don't know what else to say except you and your son will be in my prayers...Just wanted you to know you aren't alone...