Our Sister in law is trying to attach our flat

Our Sister in law has filed a 498-A case in 2012, wherein our brother fled back to foreign country. We all got the bail from Sessions Court (Anticipatory), However in 2015 she filed DV case against our entire family with Respondent No. 1 my elder brother. Further I alongwith my mom, wife and two uncles had appeared before the court and had filed for deletion of names before JMFC Court, which the court has rejected, saying about no authority & power to delete. Furthermore, our Sister-in-law has applied for residential flat of ours which is in my mom's name to be given to him for residence. How can we protect our Flat. And is maintenance applicable to us in case of absence (non-presence) of my elder brother(Respondent No.1), who has not appeared before this court and has been shown as absconding in both the cases. An Ex-parte decision in DV has been already done by their Advocate and they have also given in newspaper regarding his appearance. What should I do to protect myself, how to protect our only flat property (which is on rent L&L Agmt at present) and our entire family, please help or suggest