Robert D. Blue, son of the late actor-comedian Ben Blue, died Jan. 22 of brain cancer at St. John’s Medical Center in Santa Monica. He was 50.Blue, an accomplished artist-painter, had a long history of gallery shows across the U.S. and in Japan. He was co-founder of Davis-Blue Artwork, L.A., and at the time of his death was serving as chairman of fine art at Assn. in Art, Van Nuys. Blue is survived by his wife, Linda, and a brother. A funeral mass will be held at 7:30 p.m. Fridayat St. Paul the Apostle Church, 10750 Ohio, Westwood. The Robert Blue Foundation to aid brain cancer victims is being initiated.