Is it my normal that my mother acts like this?
So this type of thing happens a lot. My little sister who's only 15 years old lives with my mom and they share a charger. My mom asked for the charger, so her phone ended up dying overnight. My sister needed to call someone the next day and asked to borrow moms phone. My mom asked why her phone had died, and my sister told her it was because she had the charger. My mom got SUPER pissed, saying that she had completely blamed her for the situation, and started yelling and screaming. Apparently my sister tried to calm her down at first, explaining that she hadn't tried to blame her and that she was over reacting or misunderstood her. The argument started get heated anyway and my sister said fuck you to her mom, and she said fuck you back. We talked about it later, and my mom ended up saying that she thought saying fuck you was justified because she my sister pissed her off. I feel like it was wrong, in my opinion I think as an adult and parent she shouldn't be able to say those things to her child whether she said it first or not. The fact that she justified it worries me. Is this normal? Should I be worried?