Sweet, always worried, and not very bright, Stanley is the father of Beatrice, Mary, and Gloria. Stanley and Andy are responsible for keeping the vault running. They tend all the machinery and act as janitors.
On July 12, 2268, Stanley repaired the water purifier. This repair is a point of discussion between himself and Amata Almodovar when they engage in small talk the next day.
On that same day, Stanley is performing routine maintenance on the pipes in the corridor outside the cafeteria. Midway through his work, he attends the birthday party of the Lone Wanderer. Though the Overseer presents the Pip-Boy 3000A to the Lone Wanderer, it is Stanley who selects the model. Though he admits that some might find the 3000A basic, Stanley believes the series is very reliable. Before the conversation ends, he gifts the Lone Wanderer with a kid's baseball cap.
In the 2270s, Stanley is diagnosed by James as suffering from stress. The stress is caused by overworking and exhaustion. The symptoms listed in a medical file include severe and chronic headaches and eyestrain caused by the lamps in his apartment. For treatment, James prescribes aspirin. By mid-2274, James expresses reticence in doing more for Stanley. As James types in his medical file, he acknowledges that Stanley may refuse rest and that the Overseer will refuse any changes in the work schedule, and concludes that aspirin is the only option for the immediate future.
In late July 2274, James' assistant Jonas Palmer refills Stanley's prescription for aspirin.
On August 3, 2274, Stanley visits the clinic complaining of severe headaches and insomnia. Jonas confers with his patient and decides that further testing may be required. Jonas asks Stanley to wait as the clinic is prepared for the tests to which Stanley is agreeable.
Stanley is the father of Beatrice, Gloria, and Mary. Stanley's constant companion is Andy, a Mister Handyrobot, that aids his human friend in cleaning and maintaining the Vault. Stanley is friendly with the vault physician James and his child. However, he still says "Good riddance, get out" when you are exiled out of the vault after Trouble on the Homefront.
During the Lone Wanderer's escape at age 19, Stanley is encountered struggling against radroaches outside of the infirmary, but he is most likely saved by the arrival of Officer Gomez and Andy. While he states he was ordered by the Overseer to kill or capture the Dweller, he refuses to do so, saying that they and their father have always been good to him and cheers the Dweller on to find their father.
You can pickpocket him for a Vault 101 utility key during Escape! quest, however it cannot be used at that time as all closed doors are marked "INACCESSIBLE".