Telling someone he's fat and needs to change his eating habits

[Bento]

Currently I'm watching my father (SEI), who's in his fifties, gaining weight. He's fat and it's getting worse. He has severe back pain due to his enormous belly. He eats waffles with chocolate for breakfast (about 700 kcal), vow's that he eats "nothing" at work, eats a whole pizza at home instead of the cooked meal and then waffles or mozzarella sticks for dinner again. He's also a heavy smoker. I'm watching him dying slowly.

He tried magic diet pills which didn't work. My mother (IEE) doesn't want to do anything about it. As if the problem is going so solve itself. Besides, she uses the teary eye method to avoid uncomfortable conversations. Or I'm just an ass. Either way I'm out of ideas.

Last time I tried to talk to him about that I made him cry. Nothing has changed since then, so what can I do? I can't just wait for him having a stroke or a heart attack.


edit: the more I think about it the more I see it's really a question of responsibility.
@Troll Nr 007 waht's the ENTp point of view on this?