I know someone who claims to be a Vietnam Vet, and can recount quite seemingly real stories of his time as one (though I am certainly no expert) and obviously believes himself.

But ... he isn't in any records for having been over there. Something quite strange - either he is making it all up, or changed his name or something. Possibly multiple with a personality that believes he was there but wasn't physically. (At which point questions of his authenticity still apply). Or is appropriating someone else's stories, which I have heard of people doing before, because of the attention and sympathy it gives them.

Thinking of people like that, perhaps this dude isn't so strange after all? Just somehow a bit repulsive in its duplicity.

Interesting comment about the different "voices"