The biggest trick there is to learn about alcoholism as much as you can. This guy you are talking about is just not a great BF material. And he seems to be a bit abusive (the episode you described in your previous thread).
You do not have to answer this, but what exactly is preventing you to cut the ties? Have you ever tried to define it? Fear, obligation, guilt? What is so good about him that you would stay with him? These are questions you might wanna ask yourself.