Sorry, after the way the game started, I'm disinclined to offer him any freebies now.. I've made various peace offers as well, all rejected, and any he has made have had rediculous conditions attached.
He's posted several times. I've sent PMs, including one warning that I'd made peace with Ronnie and all my troops were moving to attack Zen. Even if he can't login, he can work diplomacy.
I even tried getting a 10turn peace treaty with the AI to buy him time, it won't agree. That leaves me the option of either letting the AI wander around pillaging my land, or doing something about it.
After the double moves, backstabbing, going back on his word regarding the purpose&goals of the war, and other things, I'm not inclined to cut him any more slack than I already have.