Ad, I just dropped by to let you know you have my positive thoughts
Gym membership or boxing gym sounds like a great idea!!
I don't know what to say about your S15. Sure he doesn't want to hear anything you say, but it does not mean he isn't listening.
Why not tell him you don't condone drug use (obviously) or alcohol or any other addictive behaviour, but they numb emotions and drive the everyday away. And you can understand that. Ask him to try another way. Ask him to come up with something he wants to do. If he can't, pick something and require him to commit for a length of time, like two weeks in summer hols.
I don't know, maybe worth a shot? Or pick something from my rambling you can go with
