Wife filed false 498a case what can I do.

Dear Sir / Mam My Brother and his wife stay separately from us from last 6months and now she filled 498 against my brother , my wife and my mom and me. so please guide us . they both stay separate and we stay separately then how its possible to harrase by us to her. my brother also complaint against her in our near police station. she is not in his control. they leave separate then after she not stay good with his husband and every time go to her mom house without intimate to my brother and when my brother asking her to come back then she blackmailing him with 498 case and finally she filled this. second is my brother currently do medical reports and we know she has HBSAG - Reactive. this treatment period is 1 year and its affected to him through sex and her body fluid. so its possible to get divorce on that above points. here we already stay separately then how police filled case against us. please guide us.