why do Paul’s parents ignore Erik’s cruelty?

I think they enable Erik for a few reasons. The parents seem unwilling to face the pain of the truth. They prefer to avoid stressful situations and pretend that everything is okay. They also think Erik is some kind of athletic prodigy. They feel validated by Erik's exploits on the field. I also think they are even a little scared of Erik, or at least scared of his outbursts when he doesn't get his way.