From what the cleric of Heronious said, this particular solar was as close to renegade as solars could get. The only thing that is stopping him from being a renegade is his 100% genetic incapability of rebelling.
Or so explained the DM.
Basically it was another consequence of failing in a mission given us by the husband and wife earlier in the campaign. And did we ever botch that one up.
But yeah, it wasn't terribly solar-esque of him.