Whose duty is it to look after aged parents?

Answer

It is the Waajib (compulsory) duty of the sons to take care of their parents and to maintain them financially if they (the parents) are in need. If there are no sons or if the sons fail in their obligation, then the daughters should care for their parents with the permission of their husbands. The husband has a greater right over his wife than her parents. If the sons commit the great sin of refusing to look after their parents, then the sons-in-law should allow their wives to attend to their parents. If they refuse permission to their wives to take care of their parents, then the daughters have to attend to their parents even without the permission of their husbands. But this will be permissible only if the parents are truly in need of aid and the sons miserably fail in their obligation.

The sons who refuse to take care of their parents come under the wrath and curse of Allah Ta'ala. Even their Salaat is not accepted.

It is not permissible for a daughter -in-law to prevent her husband from tending to his parents. Although it is not compulsory on the daughter-in-law to take care of her husband's mother, nevertheless, it is her moral duty to make it easy for her husband and to assist him in caring for his parents. She will gain immense reward for this service. It is haraam for the daughter-in-law to try to prevent her husband from taking care of his parents. Parents-in-law are in the category of one's parents.