Dealing with Alcoholic Dad

My Dad is an alcoholic. Drug addict too.

My mother divorced him when I was 2 and despite him having joint custody he would only come to see me every once in awhile. He would sometimes call to cancel but he usually just left me hanging. When he did pick me up, we would always have to stop for "Dad's special drink" which I now see as going to the liquor store and then 7/11 and making an alcoholic slurpee. He drove wasted with me in the car all the time.

As I got older, and I suppose more difficult to hide his addiction from, I saw him less and less. It eventually got to the point where he would call maybe about once a year, a call I normally ignored.

Lately he's been calling more often. He is definitely not sober. I'm not sure why he's trying to contact me. When I speak to him, he acts as if no time as passed since he was a (semi) present father. He'll reminisce about the same few memories he has of me, because it's all he has. He'll admonish me about not calling him and keeping in touch with him. Basically, he acts like a normal dad. "Why don't you call", "I never hear from you" etc.

Thing is...I hate it, but I feel like that's the only time that he can be happy. The rest of his family (my aunts and uncles) absolutely hate him and don't want to be around him. I'm the only one that hasn't shunned him yet. I absolutely hate speaking with him, because everything is a lie. He doesn't even admit he rarely speaks to me let alone that he has a drinking problem. Once he had a seizure because he hadn't drank and his body couldn't take the shock of not having alcohol, and he told me it was due to a potassium deficiency.

Anyway, my family is advising me to tell him I want nothing to do with him and to cut him out of my life. However, I feel like if I do this I'll be cutting the one thing out of his life that makes him happy and that I'll be driving him to drink even more, further his depression, even make him kill himself (he hasn't threatened this, it's just something I worry about).

I see alcoholism as a disease and even though I know he's responsible for his actions I still feel badly because I know he is hating his life and decisions. I recently moved and found old pictures of him when he was about 23 years old. Probably an alcoholic already but he still had a wife...baby....family...it makes me sad to see him full of promise only to know where he would end up.

I know this is poorly written but I can't organize my thoughts on this and just need some advice. What should I do?

I'm sorry if this isn't the appropriate subreddit. This is the first thing I thought of. If there is somewhere else I should go just let me know and I'll post there! Just looking for help!

TLDR: Dad's an alcoholic, forgive him or no?