If you had movie-night with Maya, you'll see one pic that shows that the dad clearly favors Derek. Maya graduated top of the class, but who's the dad cheering on? His son. She had big issues with that too. Well, that was when the pic was taken.Considering Daddy is supposed to be ultra-conservative and deeply religious, I don't imagine he's particularly pleased with Derek either. Note that Derek is eager to move into the DIK house as well. To the point of calling dibs on a janitor closet.
Derek could be acting out now, to get back at his dad for what he's imposing on Maya. I think that family is in some pretty big conflict.