I had a similar situation once. A friend who was a minor celebrity was supposed to secure some participants for an app idea. We were friends so we didn't make any arrangements upfront (huge mistake).

Come 6 months later, I'd written most of the platform, and he had put in zero effort. He then sent me a contract offering me a generous 10% of the business which also stated I agreed to work without compensation on the idea for 5 years.

I ran. As should you. Your idea is over. Take your code and go home. This individual does not have the ability to implement the idea, so it is dead without you in any event.

The world is full of these vampires. People who don't value the work we do. People who think merely having an idea is more important than being able to bring it to fruition. Has this individual offered to pay you? What was he supposed to contribute? And for god's sake why would you agree to any of this?