He has to ultimately want to help himself first. Treatment won't be beneficial if he doesn't want to change. Has he tried AA or anything like that in the past?
Are his BD and BPD being properly treated? He should no doubt be on medication for his bipolar, and receiving therapy for borderline symptoms, most often Dilectical Behavioral Therapy (DBT) is used. He is obviously self-medicating, and if he could adequately manage his symptoms, maybe he would feel less of a need to drink.
I found an interesting artical about the relationship between the 2 disorders co-occurring here:
http://ajp.psychiatryonline.org/cgi/...ull/163/7/1126. It's a bit heavy considering it's from the American Journal of Psychiatry, but it suggests that individuals with these comorbid disorders represent an interaction of both biological and environmental forces. IE: Bipolar was seen as purely biological in causation, BPD environmental. (Though on the contrary, Bipolar disorder or manic episodes are often
triggered by environmental factors like stress, sleep disturbance, etc.) For a long time, they didn't think these disorders could co-exist, but this article suggests that new research is examining that. They used to think that borderline was a varient of bipolar II, that it could progess into bipolar I, or that it was the physical or observable manifestation of bipolar disorder. Now they are suggesting that there is a subgroup of borderline patients who have "risk genes" for bipolar disorder, resulting the presentation of both illnesses.
(Sorry about that sidenote, but I partially looked it up for myself because I thought the 2 could not co-exist and that it had to be one or the other.)
Anyways, there is also controversy as to what "order" these types of things should be treated in. IE: Do you treat the bipolar and borderline issues first, or the alcoholism? Research shows that it's a cycle - one feeds off the other - so it's best to address everything at once.
That being said, do not approach him about treatment after he comes home from drinking. Do it when he is sober, and use lots of "I" statements to sound less blaming. Emphasize that you care about him, etc.
Also, if you haven't already done so, do research on his disorders. It's too easy and emotionally draining to view his symptoms as personal attacks/apathy towards you, anger, etc. (Trust me. I have a friend with schizophrenia and thought he hated me for the longest time and thought he was always mad at me. Not the case, but a part of his illness.) There are plenty of books, websites, and support groups out there to help you become more informed.
Finally, to some extent, I know how you feel. I was spending time with this guy last summer who would pretty much get black out drunk almost every night. He constantly would crash on my couch because he was too drunk to drive, and when I would actually be out with him, he would drink so much that he was verbally abusive to me.
In front of our friends. He said stuff that is too disturbing and repulsive to repeat, quite frankly. The last straw for me was when he called me at 3:30 in the morning wanting to crash. I told him no, but before I finished my sentence he was outside my apartment complex door laying on the ground. I had to half
carry/drag him up to my apartment (and I am tiny!), after which he proceeded to pass out in my bed. He woke up the next morning still drunk, gave me a ride to work, and never said thank you for helping him. Ever. I still speak with him on occasion, and actually care about him a lot. I know he could be a good person, if he just stopped drinking. I don't know if he wants to, and I used to think I could "make him" stop. Now I know I can't.
Good luck.
On occasion, I go through phases where I drink too much, but it usually lasts only a few days and then I cut back for awhile. However, it's very frustrating having alcohol in the apartment all the time. For the most part, she's "behaved," while intoxicated, but on occasion she gets emotional and/or mean...She's totally in denial too and refuses to help herself, though she is miserable. I'm to the point where I'm just sick of giving out advice and having her A.) take it but not act, B.) dismiss it, or C.) not reciprocate when I am having trouble. I've come to realize that our relationship is very one-sided and it has become about how only I can help her. I have a feeling we may lose touch for awhile after we move to separate apartments, and that is fine with me for the time being.