Fast food doesn't have to be a burger and fries. A lot of the fast food place are offering more healthy alternatives. McDonald's has had some pretty good salads for years, they are offering wraps now that probably a better alternative than a burger. Look past the burgers and see what they have. That being said, a burger isn't going to kill you. Just opt for a single burger without cheese and not the triple decker... Don't eat the fries and get a fruit and yogurt cup instead...
Silkelover, we too don't have a lot of time to cook during the week. We spend some Saturday mornings cooking up things for the rest of the week and putting it in the freezer. Usually some casseroles, or a pan of pork chops in gravy and mushroom, or a pan stuffed belll peppers, etc. The first person home during the week can pop it in the oven and not have to really prepare anything except for some canned veggies to go with it. We also put up single servings of breakfast burritos, chicken and rice burritos, bowl of stews, chili or such so if somebody needs a quick meal on the way out the door they can nuke it. We try to limit the junk we bring in the house, otherwise we would sit around and snack ourselves to death, but we keep fruit and vegetables on hand to snack on, corn chips and salsa, yogurt cups, cold cuts for sandwiches, etc. Maybe you could convince your dad to let you do some shopping and see if you can make some changes...
I'm not the healthiest person around, considering I smoke a pack of cigarettes and drink a gallon of pop a day, but I do eat somewhat sensibly otherwise...