Just because he was unethical with how he treated liberals doesn't mean he was abusive to his family. We have no idea how he treated his family. While I have no sympathy for him, I do for his family. It really sucks and is hard losing a family member, and I think that's important to recognize.
Due to human nature it's incredibly easy to categorize people we don't know in to a group of "Other" based on some trait, political view, religion, nationality, ethnicity, etc and dehumanize and demonize them. It could simply be that he did that with liberals and viewed them as the enemy(I find this type of black and white, you're with us or against us viewpoint very naive, but lots of people view things that way). But that gives us no clue to how he treated his family.
Personally I totally disagreed with his political views, and found his actions repugnant. But to blithely assume he was abusive to his family is just as repugnant.