Don't worry too much about it, he hasn't been active in 5 years and 6 days.
Nope,
just some random message, nothing really important.
But after I did - some thoughts came to my mind ;-)
Thoughts, that it should be a rule for all of the forums to not allow such usernames.
(for the security reasons.)
anyway,
So, it's good for the privacy of those mistakenly sent messages.
Best wishes.