Nparents who don't take their health seriously

Has anyone else had any experience with an nparent who won't take their health seriously? My dad is morbidly obese, has hypertension and is diabetic, has survived prostate and skin cancer (he got the latter because he doesn't wear sunscreen) and is so unfit he gets out of breath walking short distances. He also eats really badly when my mum isn't cooking for them. He eats fries almost every day, loves stuff like ready meals, frozen food such as chicken nuggets, and he drinks way too much, often consuming about half a bottle of wine per night and then having a glass of brandy before bed.

Whenever I've tried to bring up his health, he either gets angry and tells me to mind my own business, or does this weird childlike voice and repeats what I'm saying to him. It's like he's in denial about death, as if he thinks he's immortal, it's completely bizarre.