Robert Cosby Jr., the son of 'The Real Housewives of Salt Lake City' star Mary Cosby, has reportedly passed away at the age of 23. RELATED: Prayers Up! Florida Rapper Lil Poppa Has Reportedly Passed Away At Age 25 Robert Cosby Jr., Son Of 'RHOSLC' Star Mary Cosby, Reportedly Passes Away At 23 On Wednesday, February 25, TMZ published an exclusive report asserting that on Monday, February 23, Robert Cosby Jr. passed away. Furthermore, the outlet reports that Robert passed away in Utah. Police reportedly responded to reports of a "possible overdose" for a 23-year-old male.