"As much as I'd like that, I think it would be an offer better served to someone else." He's actually not surprised she hasn't noticed; she sounds young, and he finds younger people are the least likely to notice that he's blind. Something about their innocent egocentrism, perhaps it is a matter of less experience, that they can't expect something they hadn't experienced before.

"I'm blind, I couldn't properly appreciate your work." It's said with a wistful tone. "But, if you could draw a friend of mine... I'd like that, all the same." Maybe Ivy would like the picture, maybe it is just a wistful desire to have something physical to hold onto if the worst of worst happens. Either way, it's a nice idea.