Is it permissible to perform Hajj on behalf of a parent who is unable to do so due to old age and health conditions, and is it a condition that the Hajj expenses be borne by him?

It is impermissible to perform Hajj by proxy for an obligatory Hajj, except for the "Ma'dhoob" (one who is physically incapacitated) — that is, someone unable to perform Hajj in person due to an ailment that is not expected to recede. If the father is incapacitated, it is permissible to perform Hajj on his behalf, whether it is an obligatory Hajj or a voluntary one. However, if he is not incapacitated and the Hajj is obligatory, then it is impermissible by consensus to perform Hajj by proxy on his behalf, and the Hajj performed would count for the pilgrim himself.

If the father is prevented from performing Hajj, he must await the removal of the impediment. If he is then able to perform Hajj, well and good; otherwise, there is no sin upon him, and his proxy performance is not valid because the impediment is expected to recede.

As for voluntary Hajj after performing the Hajj al-Islam (obligatory Hajj), if the father is able to perform Hajj himself, is it permissible for him to perform it by proxy? There are two scholarly opinions: one permits it (the view of Abu Hanifah) because it is a Hajj that is not personally incumbent upon him; the other prohibits it (the Shafi'i school) because he is capable of performing Hajj himself.

It is not necessary for the expenses to come from the funds of the one on whose behalf Hajj is performed. If someone performs Hajj on his behalf using his own money, it is valid, and the reward reaches the one on whose behalf Hajj was performed, and the pilgrim is rewarded for his filial piety.