Yeah, and did the Shroud image eat a fish by the shore of Lake Galilee? Kinda of a silly thesis this guy has.
Te Shroud as an artifact could well have cemented and confirmed the appearance of the Resurrected Christ. But it was never wholly essential to the narrative.
I didn’t read the book, but I have heard that it was Judas wearing the sheet (he didn’t jump off the cliff, he just ran away).
And to try to repay his betrayal after the huge remorse he felt, he grabbed the sheet, and wore it around town once-in-awhile to help prove that Jesus was risen. I think he would put his hand over his mouth and disguise his voice.
This is in fact how Halloween got started. But instead of saying “Give me something to eat” you say “Trick or Treat”.
And then, after being seen by so many people over the many days (weeks?), he was afraid he might get found out, so Judas put some helium balloons under the sheet and let it fly up into the sky. (The disciples saw it and called it “The Ascension”)
The balloons finally popped over Italy and the shroud fell to the ground in Turin. The story gets pretty weird after that though, and pretty hard to believe.