Claire Novak's grandmother is an unnamed woman who is occasionally mentioned.
This woman is the mother of Amelia Novak and grandmother of Claire. She lived separately from her daughter's family, and presumably, she kept close contact with them. When Jimmy received contact from the angel Castiel, Amelia thought he was going crazy, and threatened to take Claire to her mother's if he did not seek help.
During Jimmy's disappearance while he was acting as Castiel's vessel, Claire was kept at home. When Jimmy returned, he lied about his recovery and the family reunited. However, the reunion was short-lived when demons started attacking them.
In the aftermath, Jimmy retook his place as Castiel's vessel to spare his daughter of the ordeal. A couple of months after Jimmy was taken away again, Amelia made the decision to leave Claire at her mother's place while she searched for Jimmy.
Claire remained with her grandmother for an unspecified period. Her grandmother eventually died, forcing Claire to seek out foster families while being stuck at a group home. Her fate would change when Castiel came looking for her, and helped her move in with the Mills Family.