Most Helpful Guy
Well, I would first say he's a douche and the fact that he's practically trying to tell you to join him in doing drugs after saying you don't understand what it's like since you've never done drugs. That right there is a big red flag. I would go to some counselors or experts in this sort of thing and get their help/guidance on this. I personally don't think weed is all that bad. Not that I've done weed, but I personally don't think it's as bad as the others. Meth, coke, heroin, and acid for sure are stuff he shouldn't do. After getting some help, see if you can convince him to go into rehab. If not, you may need to consider cutting ties and moving on to someone who's got their life more straight than he does.0THIS IS NOT RELEVANT ANYMORE
Most Helpful Girl
Okay... here's the thing. His behavior is annoying as hell, and I would feel the same way you do if I were his girlfriend. And there are some definite red flags there, that he is experimenting a lot and using a lot of different substances and he's forgetting shit and just being a shitty person in general. All of those things are *indicators* of someone who could have a substance abuse problem.
But the main thing is that he probably doesn't meet the *real* qualifications for a substance abuse disorder at this time. At this point, he's just a guy who is making poor choices and pissing you off by doing so, and unfortunately there are no quick-fix solutions for that. You may not like how he's living his life, but that's not really up to you to decide or change, right?
On the other hand, if you really feel he is destroying himself and going down a bad road, and you feel like it's very important that you make a change FOR him, you can just try to talk to him about his substance use and see if he can cut back/moderate with problems. If he can't, Google interventions or AA meetings in your area and those are solid places to start.0THIS IS NOT RELEVANT ANYMORE