your dad will only start getting better and recovering when he admits to himself that their is a problem, then realises he needs to get help, and then finally, commits himself to recovery. there is no quick way about it, someone can not just stop someone from drinking if they have an alcohol problem. you, your siblings and your mum need to concentrate on making sure you're all safe, and that if it gets too much you have somewhere safe you can go to. he may or may not realise the damage he is doing to your family, but its very hard to see that kind of thing when you're addicted to something as, generally, all you're worried about is the drink.
you mentioned self harm... how is that all now? as often, in times of stress, coping methods can return... if it is an issue, you need to take control of that as it is a problem. go to your doctor/school or uni counsellor, or even phone a help line at first to get some help and talk about how the problems with your dad are affecting you. not how their affecting him- he is an grown man and can take care of himself- but how they're affecting you.
its ok to think that your dad is selfish, i used to think that when mine lived with us, and i still do think that 8 years on. its ok to question whether he loves you too... i know that kills so much and i can emphasise so much, i've been there and i still am in that position... i self harmed too, for 7 years- don't suffer in silence, tell someone.
if you need anyone, just PM me. it hurts, well hurt isn't the word to describe the pain, but it can get better x