Even 1/3rd of a good business is a hell of a lot better than 100% of a bad one, or never being able to get anything off the ground at all.
"I am out of runway to continue the project. If we want to pitch this I will need a minimum x/per y with a,b,c travel expenses covered when meeting with potential investors.
If they don't have money the project stops. Simple as that. The ownership of the code could be messy, review anything you have signed/agreed to.
I would walk away and start fresh, this is a shit deal for you and if you continue with it, you'll get screwed over more 100%.
Btw, I know what I'm saying sounds harsh, but I also have to say, mad props for taking this risk. Unfortunately I think it was a bad decision but the experience probably taught you a ton and still cheaper than business school.