Maintenance

You can approach and bring the notice of your sister welfare status to  child & women welfare department officials in your state. 

It is your sister who has to apply for maintenance, but if her mental status makes it impossible then a guardian appointed by court can file a case seeking maintenance for her and the child to take care of their expenses.

File petition for maintenance on behalf of her and her child in court to appoint court commission and to obtain report from court commission for maintenance and other expenses.

He is farmar and saying I am not doing her treatment. About two to three years but we are doing all care of her and her child. Then how we deal with this situation on one hand she is mentally disturb person and long time pass she is hear. Divorse and maintenance , how procedure wise we should go.

Let her father or mothershall file suit against him for maintenance he cannot escape from maintenance. If he has ancestral land let childrens file suit for partition.