Even if you don't take equity as the payoff to the time you invested in working on this project, if you were really unpaid during all those years working on it, you likely have a strong case under employment law if nothing else, if you can document time you spent on it. It sounds like your father really took advantage of your naivete here. I can't imagine doing something like this with my son. Even if I didn't think his involvement warranted equity, paying him for working on it would be done without question.

There's a lot to learn here, obviously. One thing I'm picking up on reading your pastebin is that this is a company that grew to at least several employees, and operated without your involvement for at least a few years. There's a lot that goes into building a company, and just being around for the start of it doesn't entitle someone to half the company—this is why vesting schedules are a thing. So its worth looking hard at your expectations and being brutally honest with yourself about the role you played in the formation of the company. At the end of that, though, if you're able to honestly conclude that your role was absolutely integral to the formation of the company, you should stand firm in demanding to be compensated for that.