Alice, I can fully relate to your situation. My dad also was very abusive both physically & emotionally. I also believe that he sexually abused my sisters.
I did not mourn for him at all. I did attend the funeral, but that was just so I could see him in the casket. My brother & I wanted to be very sure that he was dead. We had been estranged from him for decades. I see no need to dance on his grave or to do anything like that. Heck, I do not even remember exactly where his grave is. I am just glad that he is gone.
Some of my siblings did try to figure out what caused him to be abusive. They tried to talk to him, they did talk to his siblings & no one was ever able to figure out why he was what he was. I personally did not care why, I just accepted that he was & that he was not likely to change. I have lived my life with that in mind. I do not regret that choice.
He never met my kids, nor my grand kids. They did not need to endure the abuse that he would have heaped on them. My kids were told the truth when they asked about my mom & dad. I waited until I felt that they were mature enough to hear what he was like. IIRC, They were in their mid teens at the time.
Twelve years later, relief is still the only emotion that I feel when his death comes to my attention. I did reconnect with my mom after his death. I am glad I did that. I recommend that you try to reconnect with her if possible.
IHTH, 48.