No good way to know if it's real or not.... It's more likely that it's an elaborate scheme to sell a book with lots of publicity.
Too much money is involved to see clearly.
I see a couple main possibilities:
1) Super natural activity that cannot be explained with conventional knowledge.
2) Agenda... clever scheme to sell books and make a living.
a ) The kid could be in on it.
b )The kid could be brainwashed from an early age. Kids are highly suggestible. The brain can fill in any amount of information given an incomplete reality. They were able to track down all the "verifying" information with relative ease, there's no reason they couldn't have done it before (or even during) the creation of the book.
From a distance it's too hard to verify anything. My only information came through the media which is absolutely the least reliable information source.