Hell, look at his Wikipedia page. And rarely have I seen a page with such edit wars, or with so damned many "Citation needed" claims. In fact, for his entire military service, there is "citation needed" for every single claim other than his spending about 2 weeks at the South Pole. And it just goes on and on after that. Including more claims of his being a senior executive for Amtrak, and other things until he shows up as an editor for a conspiracy theory magazine.
He claims to have written for encyclopedias, written textbooks, and once again not a single reference to verify these claims. Hell, after being caught lying in a House Committee hearing, he then claimed he was lied to himself in order to hide the truth. Even the Church Commission (which was certainly antagonistic towards the intelligence services) outright rejected Colonel Prouty and the claims he made to them.
And he has made some whoppers. Like that the 1960 Francis Gary Powers U-2 incident was sabotaged on purpose so it would be shot down, by people who wanted to end all talks between Eisenhower and Khrushchev. And he was a speaker for Liberty Lobby, a racist conspiracy organization that endorsed such things as Holocaust Denial, supporting the KKK, and even the forced repatriation of all blacks in the US to Africa.
Oh, and was itself the plaintiffs of a landmark Supreme Court decision. Where in Anderson V. Liberty Lobby, LL filed a string of lawsuits without any merit as retribution for Jack Anderson printing articles critical on LL. The same lawsuit that set the precedent still used today for dismissing frivolous lawsuits.
So people are really telling us we should believe the ramblings of this guy, who openly supported, was a member of, and spoke for groups supporting nazis and the ejection of minorities from the country.