He's obviously playing games, even though a nice guy. If it was me, I would respond in a day or two and not even address any of the JWisms in his message. I would tell him how great I was doing and how much I loved the job and ask how he and his family are doing. Lots of exclamation points, ya know?! I would probably do that for the principle of it, so they couldn't say I'm shunning them or whatever. Plus if it was somebody who'd been a friend at last contact and hadn't done anything personally...
Of course, you're opening yourself up for the next message to be to invite you over for a Saturday night WT study or something, so there's that. So weird and surreal, the way an exit has to work.