I don't believe him, he is now probably laughing for everyone who believes him ^^
If it is more religious than scientific, it must be 100% false, i can't doubt about it.
after 2 minutes of no oxygen for the brain, it gets serious damage so he wouldn't even be possible to read, let alone write a book.

As for what happens after when you die, well you are a conscious creation from this universe (there is no other conscious creature or as some people would refer to as a "god" involved in this)
so if you die, you can't be conscious anymore and you simply stop thinking while your body slowly gets "taken back" to the universe

of course i am not a professional in this but i don't see any other (logical) possibilities.