Instagram/Mary Cosby & Robert Cosby Celebrity Mary Cosby reveals heartbreaking final conversation with son Robert Jr. on RHOSLC, detailing his struggle with addiction and her grief after his tragic death... March 15, 2026 AceShowbiz - Mary Cosby, star of the Real Housewives of Salt Lake City, shared a deeply emotional and haunting exchange with her son Robert Jr before his untimely death. Robert Jr, who tragically passed away at just 23 years old, was the focus of a heartfelt conversation on the show that revealed the intense struggles they faced together.