Your dad sounds like mine and I would never trust him alone with my kids for the same reason.
I don't know ... I would try to imagine what it would be like to go to his funeral. If you can see yourself having regrets for not having made some contact (even if it is only a letter) after he has died, then I suggest you make that contact. It would help your sobriety not to have any regrets like that, I think.
I've actually done something similar with my ex b/f who is dying of alcoholism. I wrote him a card, just to say hi, how you doing. We spoke on the phone today, I even spoke to his wife, and me and my daughter will go visit them tomorrow.
I always thought I would spit on his grave, but when I found out he was ill, and imagined the funeral and walking past his coffin, my feelings were so different. I feel like we've made our peace; it's selfish, but I feel better now! Which is good for staying sober!
Whatever you do, as long as you can live with it is all that matters.