It's actually a nice idea. Low scale conflict means his magic will be useful, and unless those with attack magic have AoE they are at disadvantage.
What are his other options?
Running away? His land will fall to ruin. And he cares about it, even if for selfish reasons.
Fight in a duel like a moron? In best case he will heal himself to suffer more and hopes to tire an enemy. In worst, he's dead.
Assassinate fatso? Well, that would be interesting if pulled right.
Negotiate with him? That wouldn't work without display of power.