False accusation of rape case against brother in law

Hello Sir, I am living with my mother (65 Years age) , brother and his wife, His wife use to threaten us, fights daily with my old mother, I am a job person who used to work from monday - Friday morning to evening, I never indulge in their fights, she used to fight with brother but he has compromised his life due to 2 baby girls, and doesn't say a small word even when all the fault has been done by her wife, but one day wife said to my mother that she's a bitch and grabbed a stone and start beating on my mother's room. (Fortunately my mother has closed it from inside.) Then I came there and said to her not to do fight she says "I will make you threaten also by false rape case against you if you come between the fight of your mother, and also said "Me iss bhudiya ko jaan se markar hi hatungi chahe mujhe jail ho jaye", I want to know if she falsely accused me of rape case against her, police will listen to me or directly takes me to custody and put me in the jail. If she files a case against me?? I wants to know about the complete law and what else I can do to protect my mom and myself from her.