Having someone like the MC stand up for her could actually be more powerful than Josy or Derek because I'm sure she'd expect them to, but I have a feeling her Dad can be rather intimidating and that neither Josy nor Derek have been able to mount an effective stance against her Dad. But the MC doesn't strike me as someone to back down easily and he might be able to go toe-to-toe with him because he doesn't know him, all he knows is that he's an asshole bigot, so the MC would have no fear in telling him what he thinks and strongly standing up for Maya.
This could be something she'd never seen before, someone who is able to put her Dad on the backfoot for once, someone she's only known for a short time who's willing go to bat for her like this, and this might give her enough courage to follow his example. She might lose access to her loan, or her Dad might relent, but even if it's the former, there are ways to resolve that