Your question : -
"I have a query on giving NOC to my father. He says that there is a scheme in India to look after aged parents who are unable to look after their childrens."
.
It means you want to give NOC to your father, as your parent are old and can't look after you (Childern), as you still want that your old parents earn for you in their old age.
.
It will be good for you to fulfill your respensibilities, towards your old aged parent, as they did at your young age and remember whatever your are today, only because of your parent, so take care of your parent properly.
.
They can sue you for maintenance, if they want.