Who is this person?

[AussieMick]

Gene, I think you may have missed an earlier clue ...
"Considering this man's profession, one would hope that anything he said or wrote would be truthful."

He wasnt a politician. Nor a military/naval man. Nor a journalist. Nor medical/dental. Nor an actor, not involved in theatre. He did write a letter, as a 53 (if my arithmetic is correct) year old man, of some relevance to the topic under discussion.