Volunteering to perform Hajj on behalf of another Muslim who is not their relative

Q 4: Is it permissible for a Muslim person to volunteer to perform Hajj on behalf of another Muslim who is not their relative; whether it is an obligatory or a voluntary Hajj for the latter?

A: It is permissible for a Muslim person to volunteer to perform Hajj on behalf of another Muslim, even if the latter is a non-relative, dead or alive but incapable of performing Hajj by themselves due to being elderly or having an incurable disease. It was authentically reported that A woman from Khath`am said to the Prophet (peace be upon him): "O, Allah's Messenger, my father is an old man who cannot sit firmly on the back of a mount, is it permissible for me to perform Hajj on his behalf?" The Prophet (peace be upon him) replied: "Perform Hajj for your father." (Agreed upon by Al-Bukhari and Muslim)It was also authentically reported from Abu Razin Al-`Uqayly (may Allah be pleased with him) that he said: "O Allah's Messenger, my father is an old man who cannot sit firmly on the back of the mount nor can he perform Hajj or go on a journey. May I offer Hajj and `Umrah on behalf of him?" The Prophet (peace be upon him) said, "Perform Hajj and `Umrah on behalf of your father."