Mary Ingalls worked for her both part time and full time while the Ingalls needed money. (Episode 201: The Richest Man in Walnut Grove) Mrs. Whipple had one son named Granville Whipple to an unnamed husband and my have been a widower. Her son Granville later returned to Walnut Grove but sadly he had a drug addiction which eventually killed him. (Episode 221: Soldier's Return) Her fate afterwards is unknown.