Hey Cessy - My guess is that his friends already know that there's a problem. However it's not their problem as they can just go home after a fun night of partying and not worry about it. YOU are the one who has to deal with it and YOU are the one who needs to decide what to do about it. They aren't going to have any better or different ideas. It sounds like his addiction is progressing and making things more unbearable for you.
I'm just not sure what you expect to get from telling his friends. If you haven't told anybody, I guess letting it out and not carrying the secret? Unfortunately, there is nothing you can do AND nothing THEY can do. Seems like you're still hoping someone can MAKE him change, if not you, then his friends?
Sounds like things are getting much worse. Sounds to me like he's becoming less "functional". So what did you decide on that new job anyway?