Harassed by daughter in law what can we do

My brother got married 8 years ago since then we being tortured by his wife and parents.She kept staying at her place fo 4 years on off and had a daughter. My brother for sake of daughter bore her tantrums.whenever she would stay with us, she would constantly harass my mother.my father always wanted my brother to stay and so turned a blind eye..One day when she took a sandal to throw at my father and was running to lodge a false complaint my bro took her to stay separate. Since 3 yrs she is separate but my dad wants her to come back.she comes taunts my mom still my dad is adamant.what to do nw