Need a lawyer advice for my brother's case

Hello sir/mam We are 3siblings. Myself(younger female 23yr) my brother(32) and an elder sister (36). We lost our parents in 2008 and since then my brother took my responsibility as my sister was married. My brother got married in 2012 by that time i was in my 1st yr used to stay in hostel. I am not sure of how there marital life use to be before 2013 coz that was the time am back from hostel. My sis-in-law doesnt stay in our home and doesnt takecare of household responsibilities much time. She most of the time stays at her mothers place. I thought since am home to takecare of my brother so she relaxed. But that kept continuing and one day i came through one of my family friend to whom my sis-in-law messaged that she doesnt like my presence in their life . Since the guy to whom she said that is my family friend shared it with my brother and my brother argued with her for behaving so. From then my sis-in-law n i dont talk to each other. Am very pissed off with her innumerous acts for eg: on a day she took a strip of contraceptive pills to my brother and said that she found me using them etc. She used to abuse my family (mom dad n my sis) whenever my brother n she used to argue. I used to just listen ,bare and shut myself for many instances but this kept going on one day we both argued face to face. My brother is the one struggling in between all these. Me one day out of sorrow asked my brother to tell me whether am the only problem for all these things. Then he revealed that this was the situation from day one and he has been trying to digest every stuff she does.he said that she has got problem with his family (sis n me), his earnings,his social life(friends parties relatives).she makes every thing an issue use to suffer him with her words. Finally he decided to give her divorce and he has sent the notice. That lady refused to give and instead threatened him saying that she would complain against my brother me and my sister harassing for dowry . He didnt afraid of it and he was stubborn. Later she blackmailed that she is going to write a suicide note and lite her self to sue us. This happened in the month of nov 2014. The very next month i got a match and my marriage settled but the boys family wanted 1year time to settle few of their financial issues. Even i am trying for a job so thought that would be okay.from then my brother is being crushed with all these things. He neither want to stay with her nor worsen the situation thinking that it would effect my life and my sister's. But we are unable to see him struggling. We 3 now stay in the same home . I takecare of my brother . She stays with us but neither we talk to nor does she. Plz help us out to get my brother from situation and proceed legally so that we could get ridoff her with out any problem to any one.