Custody of the child

Hi, my brother's wife took their daughter away from Bangalore to Pune over 3 months ago after a very horrible argument. Since then, my brother has been sending money as per normal every month without fail as she has his daughter. The daughter is not 1.6 years old, has stopped breast milk and eats normal food. What are the chances of my brother winning his daughter's custody? His wife is abusive towards him, she cannot financially support herself or her child, she is mentally unstable and depressed as she has cut her hands several times in the past, she is currently staying with her mother who also has a broken marriage and does not wish to return to Bangalore and only seeks financial aid from my brother. He is afraid that his daughter will be under harms way due to his wife's mental instability and irrationalism. As soon as his daughter was born, he took care of his daughter 24/7 and did everything except for breast feeding his daughter. He even refrained from going to work for 1 year after birth as his wife couldnt manage alone despite having help from 2 house maids