Until he sees it for what its worth then there is nothing u can do or can say to help thats all up to him. Maybe he pictures an addict different in his head and hes not like "them" so he doesnt see a problem with it. There is nothing left for u to do at this point thats all up to him. Time for u to let it go. I understand u really want to understand and hope all of the things he is doing is all related to the drugs. What if its not? Maybe this is just who he is with or without drugs? Maybe he has just changed his interests.
U will never understand and u will probably never get the answers your looking for as far as his drug use is involved. He isnt ready to talk about it and until he is u cant save him and u cant talk to him about it. As a recovering addict myself I could look u in the eye and lie straight to your face. I didnt want it pointed out to me I didnt want to talk about it. Until I was ready nothing could be said. In my head I knew but until I was ready to talk and admit defeat there was nothing u or anyone else could say.
Addict or not him touching u has crossed the line. Time to let it go time to let him pick up the pieces of his life and decide what he wants to do. What u want doesnt matter right now. Dont get dragged down trying to get answers to things u will NEVER get the answers to.