Kinda weird the the dude is being brought up as a thread subject. So he's out, Leave it at that.
Why is it weird? People here spend years on the site conversing, exchanging ideas, jokes, etc. with someone who then disappears. Mentioning them seems quite normal.
Consider: if someone you spent hours conversing with in your personal life just disappeared and popped up elsewhere, it would be worth a mention, no? Weird that you think it’s weird.