Carla Langer was the ex-wife of Paul, and mother of Clyde Langer.
Biography
Carla's former husband left her for her own sister, Melba, before vanishing completely. It was later revealed that he had gone to Germany. (SJA: The Mark of the Berserker)
Clyde's grandmother, most likely Carla's mother than mother-in law, was an old friend of Mrs. Randall, who lived at Lavender Lawns, and tipped off Clyde on strange happenings transpiring there. (SJA: Eye of the Gorgon) During the 2009 Dalek invasion she and Clyde were away together. (DW: The Stolen Earth)
Clyde said, although he may have been lying to prove a point, that she was unable to attend Sarah Jane's wedding to Peter Dalton as she was attending another wedding at the time. (SJA: The Wedding of Sarah Jane Smith)