Dude, I am going to give you some very general advice that is nonetheless true: Shit like this never leads to you making money. Don't even start in on it. It is a waste of everyone's time, especially yours.
Just tell the guy or your brother or whoever that if they want custom software on an iPad then you need a Mac mini, an iPad Mini, and an Apple developer account, period. Don't screw around with web apps; everyone is just throwing that around because it sounds cheaper than a real custom application but it is the same amount of work and is not what they actually want.
They need to pay for this stuff for you, if they are not willing to invest even that little bit into this project then they are not serious about it.