You're much better off finding a way where you can continue development yourself without the hassle of having a major shareholder, partner and ultimately boss who has no interest, knowledge or involvement in developing it further.
Maybe he should be an advisor, maybe he should be an angel if he's qualified or have some amount of equity but not an ongoing role etc, or maybe he should just be billed for the work that he wants.
He definitely shouldn't be your boss or anything even approaching equal partner in this venture, and you have to look at the big picture... you could still be doing this crap in 2018.