My dad did this stuff too. My mom was going through chemo and he refused to take the smallest precautions like just wearing a mask. I don’t think I’d ever been angrier in my life. I’m appalled by this kind of behavior, but maybe try to talk to him. You or your siblings (if you have any) are probably the only people who can talk him down. Also, life is short and anything can happen. Losing your father on your current terms would suck.