MENTAL HARASSMENT AND THREAT BY BROTHERS WIFE

My brother is married since last 5 months. Myself and my husband were guiding my mother and brother since my father's demise and even organized Brother's marriage. Our (with mother and brother) relationship is extremely good even now. But after the marriage, my brother's wife have started abusing me to my brother and my mother accusing that I am doing kaala-jadu to malice their lives. She has threaten me for police case through my brother and mother. Domestic nuisance is a common routine in my paternal house since the marriage has happened where there was extreme peace earlier. She claims her rights in property etc. and kind of trying to get rid of my mother and my family. We (myself, my husband, my brother and mother) all are exhausted while passing through this phase and feeling mentally harassed by her and her parents. We are in fear of getting dragged into legal cases without doing anything. How can we safeguard ourselves legally & what are ways to get rid of such person socially?