I just saw a documentary on exactly this subject last week. Interesting stuff but the claims of the guy who said he was Cassidy were pretty much debunked. His sister’s account that he survived seemed a bit more credible.
Yeah, the sister was in at least one documentary I’ve seen and claimed he returned from Bolivia to the US and died here.
I guess she could be lying to get some fame herself, but I think she’d claimed this long before the TV people came calling.