Bill Madison was a pre-War American citizen who was accepted into Vault 114.
Living before the Great War, Bill, his wife Belinda, and their daughters Jean, Mary and Melissa were all designated to live in Vault 114. Their family, the Madisons, were assigned to the Residency B2 section of the vault. However with Vault 114's unending construction they may not have been there when the bombs hit Boston.
Bill Madison is mentioned only in Fallout 4.