I mean, that sounds a little judgmental. Nobody's perfect. He's stuck in a bad situation. He's been forced to deal with their BS for years. It's not easy to break over 30 years of conditioning especially because he's in a situation where she has little choice but to live with him, at least in the short term, and especially because he loves her (overall she isn't a bad person). If she and I have a disagreement, she gets upset at him about it, so he prefers to try to "defuse" the argument, and unfortunately that leads to him sometimes invalidating me.
He blames himself for his father's death because he thinks he should have tried harder to get him to go to the doctor (he even got the authorities involved at one point, but they didn't believe it met the standard for involuntary hospitalization). He also thinks he was not a good enough son and wasn't there for his dad enough (even though he lived with his dad in his late 20s and helped him with everything). That's why he's so enabling to his mom. He feels obligated to be nice to her because she raised him, helped him out at various points in his life, etc.