This sounds like me when i was 16 with my mum and dad. I was bad on cannabis from 14 to 19. I quit it in the end, and im 36 now, it just made me do nothing in life and lazy. I also did a few other things like lsd and ectacy. But only a few times. I ended up punching holes in doors in my mum and dads house. At the time i blamed it on that i was the middle child and i got picked on. But it probably was the drugs mixed up with me only being a teenager and not developed full yet.
Cocaine is a big cause for depression and suicidal thoughts.Especially when its wearing off. I wouldnt recomend any teenager or any1 taking that stuff. But i do mainly mean a teenager, only because if you get addicted to that at such a young age.. its not good at all.
When i was younger, i stopped because i wanted to, it ruined me as a person. I was thin, didnt fo out much only to a friends. My chest was bad.
Your son will only quit when he is adamant that he wants to. You cant force it on him. He will just go worse. Especially as a teenager. They always want to do the opposite you say. Me personally id just make him aware what hes doing to himself and the risk hes taking.
But that is entirely up to you. My mum and dad just went on and on at me, and i just did the opposite.
Did he go to college?