harassment by brother and his wife

we are suffering due to harassment by my brother and his wife. They both got married last year and separated within few days...we didn't get dowry in any form and took care of all the marriage expenses too...but his wife along with her mother accused us of demanding dowry, further abused us and even threatened to go to police station or might commit suicide...she is staying at her mother's house over 11 months...my brother reconciled with his wife within a few weeks of their separation...because of her threating behavior and activities my parents strictly told them to stay separately...but they refuse and both are giving mental harassment to my parents to get into the house(own house)... I'm unmarried and since I'm a girl,he tried to beat me...how to protect my parents legally ?pls help me out...