Since I already had something to work when we thought about this project, I said to my friend that he should have matured details as I was finishing my task and getting my hands dirty with the required technologies.
Pretty long time has passed and although I am fully ready now to develop, he didn't do his homework and the model isn't even ready.
In short, if he doesn't help me for the business model, where else can he help me? I think, no where! Is it better to leave him and continue myself?