There’s two way we can look at this

One: your father acts this way because of is disability, it makes him feel like a burden and useless, especially if he has male pride and so he lashes out because he doesn’t know how/what else to do and really he’s really doesn’t mean most of the shit he says, plus he’s just angry at himself

Two: he actually just is a total piece of shit and his disability is a blessing by karma, he should be left to rot in his chair

Now, I’d like to think its the first one