I am a firm believer in reincarnation and past lives. I have remembered bits of mine. There is no doubt in my mind that there are millions of people out there like this boy. And I truly hope that this one is true as well... IT's something that is very easy to fake, but because of his age, I would say it's for real.
I'm not an unbeliever in reincarnation, but I feel skeptical about this type of thing. Kids are more connected to the spiritual, but also very impressionable and some are quite easy to coach. Even inadvertently, by parents who are only doing it subconsciously. It's hard to say.