This happened to someone using stripe; a similar case where the account was suspended and the user was upset about the inability to capture revenue. I trust stripe a lot more than FB, that said, PC showed up in the thread as well as numerous suppory staff. The claim was similar, big money rev processing suspended but limited details. It turned out that the user was violating the terms and had been notified well in ad…
When you are getting the types of numbers mentioned by the app creator and you mention the name of the app, you invite unoriginal competition and Denial-of-Service attacks if possible.
If he is making this kind of money--and he mentions that it wasn't much effort to write the app--he'd kill the golden goose if he reveals what it does.