If he'd been sober, he probably would have only replied with another flat, 'huh.'

But, since he's not, he actually comes back with a subtly incredulous, "I do?"

He even straightens up a little and leans forward on his elbows, as if that might wake him up and help him think. He feels like he needs as much brainpower as he can access right now, as several things strike him at once about this.

Firstly, there's disbelief. However, no counterpoint comes to mind, so what Vincent is insisting must be true. Secondly, the fact that Vincent had somehow both noticed and remembered this in the first place is pretty mind-blowing. And finally, the greatest shock of all is realizing that Vincent has apparently been purposefully getting him ice for what seems like this whole time and he'd had no idea.

He just... he has no idea what to do with this. He has never been faced with this kind of long-term... courtesy? Is that what this is? As much as he hadn't known how to recognize it, he knows even less what to do about it now that it has been brought to his attention.