They made you an offer. You rejected it, smartly. Now it is time for your counter-offer. You already mentioned several downsides to their offer (you can't understand it, no equity, too low pay, probably lots of personal liability for you). You already mentioned that you don't even need this deal (because you are young and you could be doing other things).
I don't understand why you don't see your own leverage here. He wants you to do work RIGHT NOW. If he needs the work done right now, then he will capitulate to your demands, if you have the guts to make any. The first thing you need to do is STOP WORKING RIGHT NOW.
Then, throw away the 17 page contract and write a 1 page contract of your own, where (a) you disclaim all liability, (b) you can walk away at any time, (c) you get significant equity (if you are doing all the work, you should be getting at least 50%), and (d) you get paid a real wage ($20 an hour is not a real wage for a programmer). Give him that one-page contract and tell him to sign it if he wants you to continue working on the project.
He will object. He will want to make changes to the contract. You have the leverage, so tell him no. Definitely do not let his dad insert anything into it--you must write every word yourself, in crisp, clear, English.
If you can convince him to agree to a contract where you have no significant risk and you have significant benefits, then the deal can continue. Otherwise, you have to walk away, because his lawyer is too big of a problem. (Notice that this turns the tables so that his dad is a liability for him, not an asset.)
You might think that it is not possible to convince somebody to sign a contract where you have no risk and you receive a lot of benefits. Not True. I've done it twice on contract programming gigs. Each time, the (small) company signed the contract because they needed something RIGHT NOW. Then came back later with changes suggested (demanded) by their lawyer. I rejected all changes (think "I am not willing to sign anything except the backs of my checks"), they got mad, and they either canceled the project (1 time), or got over it (1 time). You just have to stand firm.
Personally, I still wouldn't take the deal because it sounds like your "partner" is adversarial. The point I am trying to make is that you don't have to be scared of lawyers, and there is no need to be intimidated when you have all the leverage.