Welcome!
You can't help him thru this. Really. Only he can do it for himself. He is the only one who can choose to deal with his alcoholism. You cannot really be his support system. What he needs beyond a strong desire to quit drinking is a recovery program such as AA or one of the others.
If I were you I would rethink moving in with him, at least until he has truly embraced sobriety and is actively working on his recovery. Otherwise, you can look forward to more of the same.
Why do you think you deserve to be treated with such disrespect? I mean what makes it ok with you for him to disappear for days on end and abuse you? Is that what you want in your lfie? Unless he gets sober, you can look forward to more of the sem you know.