My mother wants to perform Hajj on behalf of her deceased grandmother who raised her, knowing that neither her grandmother nor her mother ever performed Hajj, and my mother has performed Hajj before; so which of them has a greater right to Hajj?

The mother takes precedence because her right is greater than anyone else's, both in life and after death. The proof of this is the saying of the Prophet, peace and blessings be upon him: "Who among people is most deserving of my good companionship?" He said: "Your mother." He said: "Then who?" He said: "Your mother." He said: "Then who?" He said: "Your mother."