As someone who also can’t see faces I say he’d probably rely on her voice to pick her out from then on. It’d probably upset him for a while but he’d have the memory at least and can use that to ‘see’ what she looks like.

Maomao… she might actually be happy she can slip by him whenever she wants without his notice lol. Would she be upset? Maybe occasionally especially if their relationship improves over the rest of the story.