Fiction by Matthew Dicks.
This story is actually narrated by an imaginary friend. Amazing, huh?
Budo is the imaginary friend of an autistic boy named Max. He cannot be seen or heard by anyone but Max, and the other imaginary friends he meets. He exists only as long as Max believes in him.
But one day it is up to Budo to save Max....
A really good story.
I also read by this author: Unexpectedly Milo.