Copy pasting my old comment I somehow found:

Maybe she became a student-aid but was then freed, unlike Matt. And she managed to graduate.

I'm leaning towards psychology for her degree, so maybe at some point someone will need a psychological evaluation and she'll come in? (Someone could well be Matt, or maybe the newly-deafened slave having trouble adjusting to her disability.)

I think Matt might meet her (and find out somehow?), but Juana wouldn't be allowed anywhere near. Which wouldn't sit right with Matt.