Sounds like maybe his bipolar isn't being managed as effectively as it could be? When I get manic, I get angry and irritable and paranoid. I lash out at anyone about anything. Maybe it's time for him to talk to his psychiatrist about a new treatment plan (and/or if he isn't, seeing a psychiatrist who also specializes in addiction medicine - they know how to manage dual-diagnoses such as bipolar and addiction)
I agree with the others - take care of yourself first. You know that whole thing they say on airplanes about putting the air mask on yourself first, then helping others (because you can't help them if you pass out from lack of oxygen!)...get that mask on yourself first! Set some boundaries, talk to him when he is "himself," suggest he speak with his doctor about this...and getting into therapy never hurt anyone!