This is my 2 cents so take it for what it's worth:
I'm 24 and have been the alcoholic boyfriend with 2 girls (2+ year relationships). It didn't matter how much they tried to help me quit or how much they were there for me; I couldn't quit till I was ready. There is nothing you can do to help an addict quit until they are fully ready to quit themselves. Addicts can say they want to quit, but their actions and sobriety will show whether they really want it. From what you've presented, it doesn't seem like he is really 100% ready to quit.
At four months, you have very little invested. Move on and find another guy without issues. You're in school and meeting people shouldn't be too hard. I've watched my girlfriends deal with me and my alcoholism for too long. I never hurt them physically or emotionally, but they put up with a lot of stress in their lives that they shouldn't have. Don't be one of those girls. If he was the guy of your dreams you wouldn't be asking people on the internet to help with your relationship. At four months you should still be in the honeymoon phase.
Good Luck with your decision.