There's a pattern when it comes to witcher fics. Everyone's Eskel is game!Eskel. Everyone's Jaskier is Netflix!Jaskier. Geralt depends on whether the author actually likes Geralt as a character or has the hots for Henry Cavil. Lambert you can never tell until they mention his hair color. Aiden isn't in the show but everyone has a different version of him because he's a collective OC. Vesemir is just Vesemir.
None of the Witchers know how humans work. The only thing they know is that they're weaker and more delicate then Witchers, and they need to be careful when handling them.
Then Geralt brings home a bard for the winter, and all they know is that this human makes their brother happy and he's Pack now, so they need to take Very Good Care of him.
Jaskier is not impressed by these over-bearing, mother-henning Wolves.
~~~~
Jaskier: *shivers slightly*
Lambert: oh fuck the bards cold. GUYS THE BARD IS COLD!!! >:(
Eskel, appearing out of nowhere: here's some furs
Eskel: *burritos jaskier*
Geralt: *whisks him away to the nearest fire*
Jaskier, limbs trapped, unable to move: ????
~
Jaskier, working in the library: *gets a paper cut*
Jaskier: shit-
Geralt: *shoves himself between jaskier and the book, growling*
Vesemir: are you okay? Are you hurt?? Here let me see that.
Jaskier: no, really I'm fine-
Vesemir: you're bleeding >:(
Geralt: *growls louder*
Vesemir: *meticulously cleans and bandages jaskier's finger as if it's a life threatening injury*
~
Lambert: *quietly lurking behind Jaskier*
Jaskier: *turns around*
Jaskier: *terrified bard sounds*
Jaskier: damnit Lambert you almost gave me a heart attack
Lambert: what??? Is your heart okay??? Here, let me listen.
Jaskier: it's just a figure of speech-
Lambert: GUYS THE BARD'S HEART IS TRYING TO KILL HIM
~
Jaskier: *stomach rumbles*
Eskel: here's some bread
Jaskier: weren't you on the other side of the keep???
Eskel: :)
~
Jaskier: *carrying something heavy*
The Wolves: *fighting to be the one to take it from him*
Vesemir is old. Very old. We know he was already old when he was training Geralt and Eskel. He most likely still sees his wolves as babies. Even though they are adults, hunting monsters, drinking and fucking their way through life, taking drugs in company of women with horns and even building families with witches and little princesses. Doesn't matter. Vesemir looks at them and sees three cute little boys with scraped knees. Which means
Geralt bringing Jaskier to Kaer Morhen must be equivalent of a child bringing home stray puppy and begging his dad to keep him. At least from Vesemir's point of view. It's not even that bad, because the puppy (bard) is active and playful, but polite, doesn't misbehave too much, and generally a pleasant company.
The same can't be said about dirty flea-bag kitten that Lambert drags into the keep (Aiden, just as unwashed as any witcher fresh off the road). Surprisingly, Vesemir acts exactly like a dad who said he didn't like cats - meaning, the cat is now his favorite family member.
Meanwhile everyone, completely unaware of Vesemir's perspective: old man is really weird