How to gt save from false charges

My brother got married 1n 1/2 yr ago as per muslim customs n rites. Her wife delivered a baby boy ,which is of three months .his wife currently staying in her parents home,now she s denying to com home, she wanting my brother to stay with her in her parents home n to betray his mother.she s alone kid to their parents.she is not at all happy with my brother,she ll quarrel fr each n small matter. She doesnt cook at home n neithr take care of mothr in law.. He has sent notice for restitution of conjugal right.. Ll she able to make false charges about dowry or domestic violence..??? Hw to get save from those charges...please help.. Their parents had given some cash before marriage as a gift,thy had takn photoes of that..will she can make false charges of dowry.???.does it cause problem???..pls help