According to CBC News and a few other (all very local) news outlets, Stanton Friedman has passed away on the 13th of May 2019. He was 84 years old. Apart from being a nuclear physicist, he was arguably one of the best known UFO researchers of our time. There have not been any major publications about his passing yet in most of the mainstream media, but the Wikipedia article has a concise description of his life and career.
Malc has posted two radio shows in the members-only section at which Stanton Friedman was the primary guest. One is from the 1st of February 2016 (Richard C. Hoagland), and the other one is from the 18th of July 2016 (Heather Wade).