Divorce case filed can wife go abroad for avoiding hearing

My brother is from Ahmedabad and got married since last three years. His wife was studied and worked few years in US and came India for a marriage. It was an arranged marriage. He is facing issues such as. 1. Cruel behavior from his wife 2. No acceptance of his mother and his family 3. She wants to leave separately 4. Creates lots of fights It was unbearable and due to fighting they are living separately since last 7 months and now they have decided to get mutual separation. But she tells to wait for further six month. My brother feels that she is trying to move to US without proceeding for divorce and wants to harass our whole family. Her brother’s family living in US and her father is retiring in next three months; also she has started applying VISA for US. So my brother is worrying that she will leave India without divorce and will be unreachable to harass us because she is very cruel minded. So I want to know, what we can do to stop her VISA or exit from India. Please guide