Little background. Me and this dude became good friends in high school duo having similar sense of humor and honestly not belonging anywhere else. So we had each other, we went out partying, gaming etc. High school ended, I chose mandatory army service for a year to sort myself out and he chose university. I had noticed that he was prone to substance abuse before but things got out of hand for him in that year. When I got out I hadnt really talked to him or seen him but in the summer we started hanging out and partying. So we got closer again. He had dropped out of uni and didnt know what to do. I mentioned i was going to trade school and he immediately follwed my footsteps. The thing is the year appart changed him so much I dont really like him anymore. He has obvious mental issues and the drugs have made it 10x worse. I've tried to talk to him but it's obvious he doesn't want to help himself. He's bad social proof, people dont like him or the way he acts. He tries to drag me down with his bullshit, has shithead friends and is generally negative. After reading one of the 48 laws of power that stated shit people ultimately bring you down with themselves, I made a promise to myself to cut him off and not give that relationship more chances. I don't party with him anymore or go out. Thing is we still go to the same school same classes. He leeches on me and any new friends I make i feel he slowly fucks them up.

What would you do in my situation?