"...everything this guy describes has been turned up time and time again in researches relating to near-death experiences. "

Well...of course they have! Whether the sources are 'otherworldly' or not. *IF* there are glimpses of Heaven & parallel worlds...or *IF* they are just neural firing of brain cells which have had their normal activities disrupted.

To 'believe' in A is an extra step, while B is like Eliza notes, and already known to happen from drugs, dream states..etc.

'A' is just a more interesting answer.... to many. I think 'B' is the more interesting... and more likely.