Kelly Clarkson abruptly cancelled her Las Vegas shows, announcing that her ex-husband, Brandon Blackstock, was ill. Then, came the tragic news that Blackstock was dead at the age of 48. What was his cause of death?

Many of Kelly Clarkson’s fans likely remember Brandon Blackstock for fighting with the American Idol alum over their Montana ranch during their divorce and, while the couple certainly went through some contentious times,

She always wanted her kids to have the best relationship possible with their dad,” a source told People on Thursday.