Technically, as others have stated, he's done nothing wrong but IMO, it's just not something you do at a home game when everyone is friends or friends of friends, etc. I expect it at a casino but not at a home game. To me, it says something about his character if he repeatedly does it. If it's just happened this one time and he takes poker seriously like you think he does, you could be rushing to judgement and for all you know, he could have already told himself (in his head) that this was the last pot or I'm leaving at X time.
I'd give him another shot and if he does it again, then maybe put it out there, to all players, not just him, that moving forward, as a courtesy, please give 30 minutes notice when you're planning on leaving. You could play it off as a way for you to hit up people on the waiting list that you will have a seat open in 30 mins. Although if someone is a D-bag that would normally win and cash out, even with that 30 minute rule in place, they'll still essentially do the same thing by folding or not playing big pots for the next 1-2 orbits, as others have mentioned.
To me, my character at a poker table (and in life for that matter) is something I take seriously and don't ever want it called into question. I even make an announcement when I'm at a casino. I tell the person next to me "hey, you're my witness in case I win a big pot...I'm leaving in 30 mins."
I'm weeks away from starting my home games and I'm gonna have a few rules on a sign just so everyone is on the same page from the get go:
1. Show one, show all
2. No showing, talking about or commenting about cards/hands while there's live action
3. No digging through the muck
4. All flops, rivers and turns will only be run one time
5. Rabbit hunting = $1 tip to the dealer
Numbers 4 and 5 are to speed things up.
I probably won't put anything about the 30 mins notice for leaving unless it starts to become a repeated problem with the same or multiple players.