The second category is one who is unable to perform the obligatory Hajj, with an incapacity from which recovery is not expected. The sunnah establishes that Hajj may be performed on his behalf (1). Accordingly, if a person becomes unable to perform Hajj after it had become obligatory for him—despite having the financial means—and his incapacity is not expected to end, such as old age or an illness from which recovery is not expected, we say: someone may undertake Hajj on his behalf, because this is established by the sunnah.
If someone appoints a proxy to perform the obligatory Hajj while he himself is able, it is not valid. If the proxy then performs Hajj, the Hajj is counted for the proxy himself, because this agency arrangement is invalid, and what is invalid is as though it did not exist.
As for voluntary Hajj, if a person suffering from an illness from which recovery is not expected appoints someone as a proxy, and that proxy performs Hajj on his behalf, this is not permissible. This concession was only reported concerning the obligatory Hajj. Since we have said that the basic principle regarding acts of worship is that proxy performance is not permitted, he may not appoint a proxy, because no allowance for proxy performance has been reported regarding voluntary Hajj. We therefore say to such a person: if you are able, then perform Hajj yourself; but if you are unable, Allah has not made Hajj obligatory upon you, so do not perform it. And we say to one who is personally able: giving this money in charity is far better than appointing someone to perform Hajj on your behalf; and assisting a pilgrim to fulfil the obligation of Hajj with these five thousand is better than having someone perform a voluntary Hajj on your behalf.
However, some scholars expanded the scope of this matter and said: if a person may appoint a proxy for an obligatory act, then he may also appoint a proxy for a voluntary act. Accordingly, if he is incapacitated by an incapacity from which recovery is not expected, he may appoint someone to perform Hajj on his behalf. They said: because the physical demand of the obligatory duty upon a person is stronger and more demanding