My Older brother left his wife and 2 kids & live in with other woman.

My Older brother left his wife & 2 kids & live in with a woman in another city(Delhi). Now He continuously threating and abuse language by phone to my mother to kick out of his wife from home otherwise he will come & kick out my mom & his wife. My mom have love and attachment with her grandchild so she want brother come back home from the unhealthy relation with other woman. Our home is 50% in my name & 50% in my brother name. Now Me supporting to my brothers wife and kids financially. My wife and one child and brothers wife and 2 child and my mother happily living together. I am working at abroad. I am worried my brother may do crime. He hate his wife too much and the other woman he is living with my brother she also left her husband and her handicapped daughter. They are now at Delhi.. and from there threating to my mother...What should we do ? We are not yet go to police station or my brother not yet file divorce.