Mission or no mission, the project has been dead in the water for way more than six months. The most logical explanation for Paul's behavior is that he is just running out the clock, counting on time to insulate him. There is nothing that he could say that could make things better, so silence is obviously his best course of action. Don't stress over it. The money is gone, and not recoverable. Civil recourse is worthless, and criminal recourse is unlikely at this point. The game is over.