The mother was deplorable
As the title says, the mother was a despicable human being also. Obviously the father was a monster, that's a given. Did anyone find it absolutely despicable when the mom was giving her "I'm going to leave you" speech that she wanted to abandon her "rapist son"?
For years the mother continues to do nothing while her children are constantly being physically and mentally harmed/corrupted then when she does finally get the courage to tell her husband it's over she throws her son under the bus? Yes, this kid was quite the little bastard and needed some serious counseling, but the mom had no motherly instinct and had no desire to care for her son.
I'd say that sorry excuse of a mom got what was coming to her.