Bluewarning

My boyfriend and I have been together 3 years, I moved a great distance to be with him. The first year of our relationship he was sober and rarely, if ever, smoked pot. Marijuana has never really bothered me, however my boyfriend knew I did not want to be in a relationship with someone who smoked several times every day. I knew he had a drinking problem, and at the beginning of our relationship he was going to AA meetings and was recovering properly. He had previously (before I knew him) been convicted of two DUIIs and did not have a license. We worked together to get his life back on track, and we supported each other in many ways. After treatment and classes, he got his license back and continued to stay sober. I can't remember exactly when, but he slowly began to drink again. I watched his behavior slowly change. When he would drink he became verbally abusive, and his mother tried to help me deal with this, as she was afraid this would have happened. After about another year he was still being relatively abusive, and not only when he had been drinking. After months of contemplating leaving him and after several huge blow-outs, I broke up with him. We had a talk after all of his things had been moved out, and I stuck by my decision while still giving him a chance to really hear why. He told me he hated the way he was acting and that he didn't want to treat me that way; he didn't want to become like his father and he didn't know how to stop it. He also told me that another reason he hurt was because I used to be very supportive of him and he saw me leaving him as me giving up, that I didn't love him enough to help him. I did tell him that he was misunderstanding. It took me months to really understand that his drinking and his anger wasn't something I could control. I told him that I couldn't stop my life completely to mother him and support him forever. He said he understood and he apologized for everything he had done.
After a couple of months, we started talking again and he had been getting his life back on track. He was taking steps to buy a house, he had just been laid off right after we had broken up but was working with a friend in the mean-time while looking for another official job. He took me out on a few dates and started to treat me the proper way he said he wanted to. I made sure he knew that we were going to take things very slowly. After a few months we got back together, and I found support from his friends' wife who apparently has been back and forth with her husband with similar issues.
It has now been several months since then and I have not encountered his emotionally/abusive issues as of yet. However lately he has begun drinking again. He does not drink hard alcohol anymore, he drinks beer but he will drink 7-12 beers most nights that we spend together. Some times I go over to his place and I see his bedroom is littered with empty beer bottles. I have spoken to him about this, and told him calmly that this is not good for him. He says he doesn't like "feeling like sh*t" and he drinks to combat this. I tell him that the drinking doesn't help that. I have no problem with a person drinking hard liquor occasionally on a weekend to let go, or having one or two beers to let off steam after work but this is not the case.
He is depressed and he does not open up to me what is making him feel this way. During his sober periods he explains that he gets non-stop nightmares no matter how many months he had been sober. Awake, however, he just seems more normal to me. He seemed happier, even though some times he would insist otherwise.
He absolutely refuses to drink and drive, and I am very happy about that, but I don't know how to show him that his is again going to dig him into a hole of even worse depression. He does not like medicine and he did not like going to his court appointed AA meetings, so I am just not sure how else to get him help. I feel like I may be drowning right along side him and I don't know if I can keep up with this battle.
Does anyone have any advice of what I can/should do?