Why does that sound like Bill Hicks to me?

I've never taken Thonnir in there. The other guys who follow you out to the cave are at least honest in their cowardice - it's too scary! Let the PC go in first! But Thonnir is like "you cowards we must kill these vampires rah rah rah" and when you tell him it's okay you'll do it alone, he immediately makes an about-face. Big talker, but that's about it.

Sort of like Enmon in the Heart of Dibella.

"My daughter has been kidnapped by those Forsworn bastards and we must make them pay! I'll kill them all! Forsworn blood will drench the ground and their skulls will form a monument to the folly of kidnapping my child!"

"No, you wait here."

"Oh, you're right. I'd just mess it all up. I'm not a fighter. And by the way, once you've rescued her feel free to whisk her off to some other city, I don't need to ever see her again or anything."

Maybe that's why they did Fallout 4 like they did - the whole "agitated parent missing a child" thing was so underdone in Skyrim that they... phoned it in for Fallout 4 too?

Oh, Thonnir is better than that. He stands way too close so he's always shoving you; he rabbits on inanely the entire time; he's noisy, not just "refuses to sneak" noisy but "makes a lot of racket" noisy. He triggered combat with one of the thralls while I was sneaking that I couldn't trigger on purpose on my own, not even jumping up and down and casting spells. And if you need to turn and run, you smack right into him because he's standing right behind you. And he's essential so he can't get killed, but also pretty fragile, so he spends most fights down on one knee.

To add insult to injury, when my girl got captured by SD+ (entirely his fault I might add), he promptly changed sides and helping vampires with their training program.

The joke I heard from a friend of mine more or less he same as I told it here. Could have been Bill Hicks originally for all I know. It sounds like his sort of thing.