I don't understand why he didn't nail down his equity situation before doing any work. Yeah, it's pretty shifty of the 'founders' but then it's pretty basic for techies, especially early startup engineers.
Fortunately, I had written proof that I'd told them this was going to happen (the bottom of the previous invoice), so I did get paid, but I never did see those shares. Shares are a gamble anyway, and if the CEO doesn't read invoices I don't see them lasting very long — I don't loose sleep over this mistake, just use it as a lesson for the future.