I agree also.
I had a abusive parent too but would never write something so hateful.
Some people cannot handle certain situations because of mental illness
and this could be the case, as I would like to believe was my parents' problem.
That said, I would not have written something like this in my mother's obituary. We had our problems, but we did love each other and there were other people who loved and cared about her. There would have been no need to disrespect them in this way. It's hard to believe that this woman was THAT bad 24/7.