Gail Pilgrim (elder) was the mother of Gail Pilgrim.
She suffered from a severe psychiatric disorder, and two years after the birth of her daughter she was admitted as a patient to the Aegimus Medical Facility. John Pilgrim kept the truth about this from his daughter for many years, before finally revealing it to her in 2205.
This enabled Gail to reconnect with her mother for the final years of her life, especially after she moved to Planet Abassi to found the Pilgrim Space Academy.