I frequently visit a coffee shop. One day a person started a conversation. He asked if I know any developers. I said I am one and what is he looking for. He sat down with me and explained me his requirement. He did not explain any technical information, but only explained how much money he is hoping to make. He also mentioned a famous website, and said he wants to compete with them. He has asked me to work for him and if I say yes, he will rent an office space and in his words, 'Together, we can make big money'.
He had a previous team which made some progress. He showed me his website and it seemed minimally functional, but looked like it needed some work.
Now I really want to believe this person, but this whole thing seems unusual. Also, I tried to remember all the figures he mentioned about revenues, number of users etc. I went online and checked, and most of them were not correct. (But I am ready to grant the benefit of doubt)
How should I find out if this company, person and his business is genuine?