sentences:  Gilbert and his wife Barbara Crane adopted Melissa Gilbert who played Laura Ingalls Wilder and her brother Jonathan Gilbert who played Willie Oleson on the NBC TV series "Little House on the Prairie".Gilbert was believed to have died suddenly of a stroke on February 13, 1976.In her autobiography, his daughter, actress Melissa Gilbert wrote that, due to his suffering from constant pain from injuries incurred during WWII, he committed suicide.