The only thing I can say is just remember that there is only so much you can do. I had an alcoholic boyfriend once too. I loved him alot. I did my best to be supportive and tried many time to get him to quit. No matter what I did he always went back to drinking. While I knew quitting was very hard for him I realized there was only so many things I could do or say to motivate him. I don't feel bad about leaving him because I know I did everything I could to help.
I'm not saying you should give up on him. Just know when to say enough is enough and don't let him be abusive to you even if its just on the phone.