Is it permissible to perform Hajj on behalf of deceased parents who never performed it, and is it better to start with the mother, and is it permissible to borrow money to appoint someone to perform Hajj on behalf of the other?

The mother's right to dutifulness is greater than the father's. The Prophet (peace and blessings be upon him) clarified that the mother is the person most entitled to good companionship three times, then the father the fourth time. This is due to the hardships the mother endures during pregnancy, childbirth, and breastfeeding, followed by her shared role with the father in raising the children. The majority of scholars hold that the mother is preferred over the father in dutifulness, while some say that dutifulness to both is equal, but the correct view is the former. Accordingly, the mother's Hajj is given precedence over the father's if both are supererogatory. However, if the mother's Hajj is supererogatory and the father's is obligatory, then the obligatory Hajj for the father takes precedence, with the emphasis that the son should perform Hajj himself if he is able.