Is it permissible to pay the cost of Hajj to charitable committees to perform Hajj on behalf of a blind mother who is over seventy years old and cannot be taken for Hajj due to the unavailability of a woman to attend to her?

The mother must hire a woman to accompany her during Hajj if she is able to do so, because by doing so, she is considered capable and able to perform Hajj. If she cannot find a woman to accompany her or someone to volunteer for it, the obligation of performing Hajj herself is lifted from her, and she must appoint someone to perform it on her behalf. You must perform Hajj on her behalf if you have already performed your own obligatory Hajj. Similarly, if your father died capable (of performing Hajj) but did not perform it, you must perform Hajj on his behalf, because it is a debt owed to Allah by him.