I set a boundary
Woohoo! I set a boundary yesterday and told my dad not to call me if he's been drinking. If he does I will tell him I don't want to talk to him. I told him that these conversations aren't beneficial to him and they are hurting me, so I needed to put my foot down.
He was a little taken aback, but he seemed genuinely willing to make an effort so that's progress as far as making this situation manageable *for me.*
Next step is telling him I won't take him to buy wine when he comes to visit...this one may be trickier and I'm not sure whether I need to give him a heads up beforehand or not. I have a few weeks to decide.