What is the ruling on a married daughter providing full care for her sick aunt, and what is the extent of its permissibility and priority over the daughters-in-law in this care?

If the intent behind denying religious responsibility is to negate obligation, then the care of the maternal aunt is not obligatory upon the woman, nor upon the daughter-in-law. Rather, it is obligatory upon her children, for they are religiously enjoined to serve and care for their parents in the most complete manner. However, if the intent is to negate permissibility, then there is no harm upon the woman in caring for her maternal aunt, as she is in the position of a mother. But if she is married, the permission of her husband is required. And caring for her is better, as she is a relative by kinship.