My friend's mom verbally abuses her? help?

So my friend Natasha, she's one of my best friends so she tells me like everything. i even see it first hand. Her mom like verbally abuses her all the time. Nothing she does is ever good enough and always wrong. Her dad is Jewish, and her mom basically made fun of her for it. [They're divorced] Today, my friend was over and when her mom came to pick her up, I sat on my porch and she left. She came back a couple minutes later crying her eyes out because her mom flipped crap on her and called her a bi'tch. I wanna help my friend but I don't know what to do?