Brandon Blackstock spent his heartbreaking final days surrounded by family, but his ex-wife, Kelly Clarkson, was not his primary caregiver.

Brandon Blackstock, the talent manager and former husband of Kelly Clarkson, died of melanoma, a form of skin cancer, on Aug. 7. The Silver Bow County Coroner Dan Hollis tells PEOPLE Blackstock "passed away peacefully at his home in Butte,

Brandon Blackstock's official cause of death has come to light, days after the talent agent and ex-husband of Kelly Clarkson died of natural causes at age 48.