Hilda Schofield was the mother of Cassandra Schofield and the grandmother of the Seventh Doctor's companion Hex. (AUDIO: Project: Destiny)
Hilda took care of Hex alongside his father. Hex believed her to be his mother until he was six. (AUDIO: Night Thoughts)
She used to take Hex to the seaside every summer when he was a child. (AUDIO: World Apart)
The Seventh Doctor came to visit Hilda to inform her of Hex's death. While she initially accused the Doctor of letting Hex die, she eventually grew to accept it. (AUDIO: Afterlife) Sally Morgan lived with Hilda for the next two years, before Hilda eventually passed away. (AUDIO: Signs and Wonders)