I read his book, and honestly, there's no evidence beyond his word that it isn't a dream. People have dreams where they leave their bodies all the time, people dream about what they think about. I remember when I was seriously questioning my opinions on Heaven and Hell, I also remember dreaming Jesus gave me an aerial tour of Hell and a glimpse into Heaven, and the Hell in my dream looked a lot difference between his and mine. Not to mention the whole lack of scriptural support some of his claims (even how many verses reference Hell, it's about a 10th as much as he thinks). At most or best, it's a intense and vivid nightmare misinterpreted, at worst, it's a deliberate scam.