Nice! Seeing Brad with an apple made me smile.
She was never allowed to call him dad or seeing him as such growing up, he did drugs in front of her and forced her to kill people at a young age. She never got to discover the world or get in touch with others. Once she was kidnapped she realized how fucked up her situation was (in absolute, it's not more fucked up than any other options she has imo). I guess her goal was to get away from him and finding her own identity as soon as she knew this was possible. She probably doesn't have a lot of empathy as a (abused) child and even if she says she understood Brad's trauma, that's false. He never told her about Lisa.
Her character isn't that great or even likeable, but it's not a typical brat either. I don't get what are Austin's views of his female characters though, as he said that Lisa was the one behind all the mess in Painful.