Is it permissible for me to perform Hajj on behalf of my deceased brother, who performed Hajj multiple times, with my intention for Hajj this year, or should I commission someone to perform Hajj on his behalf in exchange for the Hajj expenses plus an additional amount?

It is permissible to assign someone to perform Hajj on behalf of the deceased, and the reward of the Hajj will reach him, provided that the adult heirs consent, or that it is a donation from private funds. It is not permissible for it to be from the deceased's money unless he bequeathed it, and then only within the limit of one-third [of his estate]. It is permissible for someone who has performed Hajj for himself to then perform Hajj or dedicate its reward to the deceased, and to dedicate as much as he can of acts of devotion and good deeds.