This is my first post here but I decided to reply because the original post reminded me so much of my own family situation when I was a child. My father was an alcoholic who got sober when I was about 11 years old. After getting sober he became a classic "dry drunk."
There is nothing worse than a dry drunk. They are angry, nasty, bitter human beings. Not everyone who quits drinking follows this pattern, but I think the ones who do are the ones who are more likely to have had some sort of serious underlying psychological problems to begin with. You mentioned him hating his mother, my father was the same way. HUGE issues from childhood that he had never dealt with that ended up manifesting as just generalized rage at the entire world.
My dad eventually improved -- dramtically, although it wasn't until years later and after many years of therapy and being placed on medication, and also I think just getting older and mellowing out a little. Before he "got help" I honestly think that he was worse as a dry drunk than he ever was as an active drinker.