Maintenance to be Paid

Hi, I am asking this question on behalf of my brother. He married a girl in December 2019. They were having issues since very beginning. After 5 months, she left the house in the month of May and asked my brother to pick her back up in June 2020 after 1 month. Then, her family came to our house and fought in June 2020 by threatening my brother and my parents. She did not leave, but continued to stay. Meanwhile things did not get better, she filed a complaint in Mahila Ayog in Delhi in July, however continued to live with my brother and asked the aayog not to pursue at that time. Then finally, she fought and left the house in September 2020 and took her stuff with her. She used to ask my brother to separate from parents, which he didn't. But after she left, my brother in a bid to save marriage found a rental place and moved. The day he sent her message about rental home, the mahila aayog called him and told him that a complaint had been filed against him. 2 sessions of counselling were done with no result. We are about to move to the maintenance stage as his wife is greedy from what we have seen from her. My brother earns almost 1 lakh per month and she earns 45,000 per month in hand and is a PhD, whereas my brother is a simple engineer. We have also got to know that she has taken a loan after she left my brother (probably in a bid to enhance maintenance by showing greater expenditure). What possible maintenance can my brother be asked to pay. He is now living in a rented accommodation and helps my parents (who are senior citizens) by paying them monthly money (which he has been doing for more than 1 year now).