Vincent gives the traditional "oh!" when Irahl reveals the shirt's mystery--because yeah, that suddenly makes a lot more sense. And now that it's pointed out, he can smell it. Underneath all the blood stains, this thing's definitely been in Seth's house.

Which is part of what gives him pause when Irahl asks his silly question. Seth's always been very weird about his things. He rubs the fabric between his fingers a little more, as if he could ascertain something about it's quality or condition by doing so. He can't, he's the least qualified person to talk about clothes out of all three of them.

"Depends on his mood," he eventually answers, smirking a little, "Either he'd rather burn it than take it back, or he'll be on your fuckin' case for the rest of your life about it. He'll show up to your funeral and take it off your corpse if he has to."

He's joking, but... He's also not joking, as per usual.