I think he and Stevie could get along well! She'll be friendly, at the very least. And she works as a potioneer in medical, so maybe she's part of his treatment team? Also, she's just finding out that she's cross-species and it's a lot to deal with, so while she wouldn't necessarily pry, it could def be interesting if we can find a way to get them talking about it!!
Matt will be super curious about his condition and assume it's something that everyone else understands. He won't quite get the fraught nature of it and might ask some insensitive questions before he catches on!