Oh hun. Have you talked to him about this? maybe telling him how you feel will change his view.
You're mums right though. A person needs to want to get better to get better. You can't force anybody.
Maybe you're dad is suffering from some kind of depression. I think it's hard being a dad. sometimes you feel like you haven't provided enough for your family and it can get you down.
My own father doesn't care about himself either. he doesn't drink but he smokes a pack or two a day and is overweight.
I think your dad needs some help. you being the kid may just be able to talk him into it. Maybe. Tell him how much you love him and how much it's hurting you to see him like this and how much all he does hurts you period. Tell him how you'd feel if he was to die and tell him from the heart. That's all i can suggest hun.
Take care. xox and remember it's not your fault. some ppl are just like that.

your moms right you really cant help someone who doesnt want help. but i think its definitely mental. look outside the box. do your parents ever go out any more? maybe they should go out to eat or see a movie keep things fresh and make them realize that there is still something to live for. its normally hard to get through to someone who has lived a long life. some people can be very stubborn. he is sounds very angery at himself. but since he doesnt know what else to do he drinks. has he always been an alcoholic? if so this is a normal part of his life and i dont really know any other way out of it beside professional help. but if this alcohol is just beginning to be like this he is trying to cover up his feelings. having a heart attack can really affect a person. he might just be so scared but afraid to admitt it because hes a man. hes saying he dont care becaus ehe thinks thats there is nothing he can do about dying at this point. hes young! he still has years dont give up.

Beat him up, while telling him your feelings on the issue.

But do it while he's sober, so he won't forget it. Trust me, my dad was a real a**hole with the alchohol, then once I was old enough to beat him up, I did, and told him he was ruining everyone's lives.

He sobered up, completely crushed by what had just happened. I mean, his own son was livid enough towards him to wale on him.

EDIT:

Actually, I don't condone violence. Maybe it's just better to tell him your feelings, and tell him how badly he's hurting everyone.

What about a hobby?....Something that he used to enjoy that he has forgotten to remember....A person who is aging needs a purpose....A reason for living....Somewhere along the line he has lost his way....What about the two of them taking a vacation?....Going back to a place in time when they were young?....It sounds to me like he is in a mid-life crisis and can't find his way out of it....I think that if the drinking and smoking stop, that he could go forward....He sounds to me like he is trying to die and get it over with....Kind of a cop out in a way.....Maybe this is his thinking as he has already had the heart attack which in his mind signals "old age"...Honey, growing older is not easy for many people....I have kind of skipped through it so I don't know.....

I believe he is scared, and just can't find the right door to open to get out of his own self induced jail.....I would work on getting him away from drinking and smoking and get a hobby...Even if sharp words are spoken....Definately make AA a must.....It is a great support group and may bring him peace....

I hope everything work out for you....

Best wishes,
Caroline