Undecided custody mother got married immediately after divorce

Respected sir, This problem is of my brother. He found out about adulterous relationship of his wife with her boss in school in 2015 and didn't want to live with her. He and his wife flied mutual consent divorce petition in 2015, which was unilaterally withdrew by her immediately in a month or two. At that time custody was to be kept at our home with my brother. Then she filed for restitution and alimony / maintenance case in Ahmadabad, along which she has asked for children custody. We were agreed to give her custody in reply but she was not willing to take t when judge asked to take. My brother filed 13 A in Rajkot ( where he lives ) on grounds of mantle cruelty and adultery. Divorce was granted by court before 2 months. No mention of custody done in court order. Now we came to know before few days that she got married to someone just few days after court's decision. Now, my brother is having heart attack because of so much mental stress and torturing from her and my parents aged 70 years are too in bad health. We are not capable to take care of basic needs of children. Can you please help us regarding how can we give custody to their mother. Current age of boys are 13 years and 8 years.