I'm really worried about my dad's health. He's almost 60 and has a family history of heart failure.?

He eats everything he sees but avoids the healthy things. His belly is bigger than me rolled up into a ball. Everytime I try and help him (veggies, excercise, nutritionist) he pretty much screams at me saying he's fine and that my weight loss is affecting what I see. What should I do to prevent him from having a horrible early death?