Kelly Clarkson has “been devastated” for her kids River, 11, and Remington, 9, as their dad Brandon Blackstock, who died on Thursday, Aug. 7 at age 48, faced cancer for three years privately, a source tells PEOPLE exclusively.

Brandon Blackstock, Kelly Clarkson's former husband of seven years and father to kids River Rose and Remy Alexander, died "surrounded by family."

Clarkson’s last Vegas show was on Saturday, Aug. 2 and she was set to resume her Studio Sessions performances on Friday, Aug. 8 as the first of four more shows in August at the Colosseum at Caesars Palace. The residency is set to resume in November.