Jack Harkness's mother

Javic Piotr Thane's mother lived on the Boeshane Peninsula with her husband and her two sons, Javic and Gray.

Following the attack by the "worst creatures in existence," she and Javic were the only survivors in their family; Gray was captured after Javic accidentally let go of his hand, and Franklin was killed by the creatures, with Javic returning home to find his mother cradling Franklin's corpse. (TV: Adam) Jack later remembered his mother's anger over his father's passing. (PROSE: The Man Who Dreamed of Stars)

Javic, then going by "Jack Harkness", later implied in a conversation with Esther Drummond that he did not know what had happened to his mother, suggesting that she was still alive when he left his time frame. (TV: The Categories of Life)