So, I've found him in the cemetery a while ago, and I discovered that, as a Paladin, I can make him believe he has to marry Nathalia, in which case he runs away, which means I can't get the XP (and some gold) reward for completing the sheriff's quest to bring him back, or I can force a fight, in which case I do get some gold from the sheriff.
I was wondering, though, if there's some way of convincing him to return to Hillbrandt. Maybe with an other class (the Thief, most probably)? Or is it not possible at all?

I tricked him with the marriage thing as well. Not sure if I can actually arrest him and bring hm back to town.

It's not possible to arrest him. You can trick him to avoid a fight or kill him.

Thanks, this is what I was wondering about.