what now?

hi im jo, im 24 and the daughter of an alcoholic father. my dad has been drinking for as long as i can remember and for as long as i can remember family life has always been hard. I think dad started drinking as a social thing that he would do with workmates at the end of a hard day at work. this would be almost normal to a lot of people but the normality stopped when he would have to have a drink at home too. I dont think i have a memory of my dad where he did not have a bottle of cider next to his chair. that fact makes me so angry. I know that i was about 10 years old when i stared to intervene in my parents arguments and it was then that i started to realise that life without dad would always be better. mom had a really terrible life with dad, she obviously loved him and wanted to help him through his addiction, but she was also so scared of him, and that is why it took her so long to leave him for good. after years of constant mental (and sometimes physical) abuse, years of having no money for herself and years of feeling like she was the one that was no good she managed to break free from him. it was mom that had to do the hard work like finding him a flat and getting it furnished because if it was up to dad he would have happily carried on living in our house and making us all so unhappy. he has been living on his own for 3 yrs now and my mom has never felt better or happier. dad has been in rehab more times than i care to remember but he has just never been strong enough to keep sober for very long. since mom and dad split up i have done my best to take over her role of looking after him, i have 2 younger brothers but they are both still so angry with him that they dont want anything to do with him. i know they love him but they are strong enough to say no to him. my dad relys on me and it is getting me down because i feel like my life is ruled by him. years of drinking have certainly took its toll on his health, he has sever pancreatitis, and as soon as he hits the bottle he loses the use of his legs, they completely pack up which leaves unable to get anywhere without help. i do his shopping for him and take him wherever he needs to go. he does give up the drink sometimes, but when he does he has to be on an anti fitting drug to stop him having seizures, and i have only just realised that it is never going to be for ever!!!! I think that i have now got to the stage where i just dont think i can do anymore for him, but this is where the guilt kicks in, do i leave him to rot and hope that he will see sense to become sober or do i carry on being the dutiful daughter to the sick father but never getting anywhere? I have a 2 year old boy and so far i dont think any of this has affected him but im scared that as he gets older he will find himself in the same situation i was in but with his grandad instead of his dad.