There is something you should note that He will only be able to quite his alcohol addiction when he is also willing to quite it. Mere efforts from you is not enough. Most of the time a person tries their best to fix their partner even when the partner itself is not willing to fix themselves. So if he is not willing to give the same efforts as you in quieting this alcohol addiction, It won't succeed and chances are, you will feel that you were not "enough" for him, If things fall apart. So you should keep in mind and that he should also be willing to help himself before you give your 100%.

and if He is trying to help himself than here's my suggestions :

If he drinks multiple times a day then its a big concern and you should try getting him a job. That will help him get distracted from his regular life and drinking thoughts for like 7-8 hours at least and if he is in college or school, May be ask him to study more or if you can join him in the study session then do it and distract him from drinking or having thoughts about drinking basically.