A press release I just received for Navy Wings of Goldstates that the book explores themes including (at the top of the list) "the only thing that prevented George H. W. Bush from being captured, executed, and cannibalized." I have requested a review copy and plan to report back to readers of this blog.
UPDATE: The book's publicity agent, in sending it to me, told me the short answer is "his brotherhood." The story is told in some detail in Ch. 19, which recounts the story of Lt. (j.g.) Nathaniel "Blackie" Adams, a key participant in Bush's rescue.