Watch: Kelly Clarkson's Ex-Husband Brandon Blackstock's Cause of Death RevealedMore details about Brandon Blackstock's death are coming to light. Following the tragic passing of the talent manager-who shared kids River Rose, 11, and Remington "Remy" Alexander, 9, with ex-wife Kelly Clarkson-at 48, his cause of death was determined to be natural causes related to a diagnosis of melanoma, Silver Bow County Coroner Dan Hollis confirmed to People.