I find it odd that Paul was "not permitted" to talk about heaven, yet an exception has been made for Colton Burpo.
I also hate it when God gives his people something (a word, an experience, knowledge, etc.) and then they glorify Him by selling it to others. I know paper and printing cost money, but if God is really allowing this child to give extra-biblical knowledge of Heaven, then put it in a blog or on a website for free.
Also understand that all demons were once angels and they have all been to Heaven and know about it, yet have been bound to reveal it. Why>
Without Faith, it is impossible to please God! Hebrews 11:6