I can relate big time. My estranged mother passed 6 years ago. In the very end I had to decide if i wanted to see her one more time. I chose not to. I felt horrible, but I was protecting myself. What good would it do to have her verbally abuse me one last time? She was an abusive alcoholic like your dad.
The night I decided not to see her before she died, I got soooo drunk. I got drunk after the funeral too. I wish I hadn't handled it like that. I'm still struggling with addiction, but I vow that i will NEVER put my son through what I went through and that is why i have to stop this. Right here right now.