What should I do with my alcoholic father ?

My dad is very good at taking the spotlight off his problem and pointing out everyone elses (hes been a drug addict for 30 years as well as alcohol but hes been clean from drugs for awhile for hes on methadone but still drinking). We always get into altercations when he blacks out and points the finger at me when the police are there. All i try to do is love him and have a relationship with him and the only time we are good is when im drinking with him. Now that im pregnant and not drinking i see all the ugly things alcohol is doing to him. I cut him out my life and he went to rehab and only lasted 2 months. he came strait to my house and started being the dad i never had (he's been drinking since before i was born). Unfortunately a week later he went back to drinking hard alcohol and went back to his normal ways. He makes me angry and hes disrespectful. I dont know what else to do for my heart is telling me to be strong and let him know he cant even hear from me unless he's sober which i know wont happen. My mind is telling me to put up with it for i might need him one day. My pride is telling me f-him. Does anybody have any smart suggestions ?? My brothers gave up on him and they tell me he wont last to much longer due to the abuse and im the only one trying to be a good daughter but is it worth it ? or do i just wait until the day hes gone ;(