What was the issue for Stephanie and her parents (General)

Were both of her parent mentally ill or just one?

Mr. Douglas physically abused Stephanie and beat her all the time, and she had injuries and her mother ignored them. I cannot remember but I think she alluded to sexual abuse too.. And Mrs. Douglas knew, but chose to pretend it was not happening or did not happen. When Stephanie confronted her mother (Betty White) she told her mother he life had been one bottomless pit of rage. Her mother said that IF she was disciplined, then she probably deserved it. In the end it was Pam that got in their mothers face and told her that she knew what was happening because she and her mother listened all the time to Stephanie's screams her mother would just make Pam play the piano louder and tell her to ignore it. Pam told Stephanie she tried to talk to her about it, but Stephanie told her she did not want to talk about it. She confronted her mother and screamed at her "when he began beating me you would just take Pam and leave the room, how could you do that to me. How could you sacrifice me to his abuse?"

Were both of her parent mentally ill or just one?

I didn't know that either were suffering from a specific illness. I thought her dad was just abusive, and her mother pretended it wasn't happening. But perhaps mental illness is why the father was abusive.

Were both of her parent mentally ill or just one?

Stephanies dad was abusive and her mom failed to protect her.