It sounds like your dad doesn't know how to help you. Unfortunately living in 'his' house, you are kind of at a loss if he doesn't want to help you out by hiding his junk food at all. I will say though that once I was resolved to do this, it doesn't matter what junk is in my house (and there always is). I just don't eat it. I will fix my hubby whatever junky snack he wants and then fix myself something healthy. Sometimes he wants my healthy snack too and that is what I am going for. But sometimes you have to understand that just because you want to change yourself doesn't mean your dad is ready or willing to change himself.
How old are you? I am sorry that you are having this battle along with trying weight loss.