If he's a premium member, his account automatically activates vacation days if he times out.
Resetting Games Lost on Time
He is not a premium or gold member. And the notification was different in any case - I actually got the pop-up saying that I'd won the game, and showing the rating change.

So I was playing a guy in several games, all of which he wound up losing on time (2 day timer, he forgot to check).
Somehow he managed to reset the timer (or something) and move again. I thought the games were over, and I wound up losing on time.
Anyone know how he pulled that off?
You only have one recent two-day game you list. The rest were from September 2016. It is probably too late to do anything about them but you could open a ticket.
https://support.chess.com/customer/portal/emails/new
You recently did win a 14 day/move game on time against that same player.
So I was playing a guy in several games, all of which he wound up losing on time (2 day timer, he forgot to check).
Somehow he managed to reset the timer (or something) and move again. I thought the games were over, and I wound up losing on time.
Anyone know how he pulled that off?