Kelly Clarkson  continues to prioritize caring for her two children following the  death of their father, Brandon Blackstock .

A source tells PEOPLE that the singer-songwriter was “devastated” to see  her two children, River, 11, and Remington, 9 , pass away on Thursday, August 7 at the age of 48, after a three-year battle with cancer.

“When she knew he was sick, she was protective of him for their sake,” the source said. “Kelly always tried to keep things in order. It was clear earlier this year that Brandon wasn’t feeling well. She was devastated for the kids.”

Clarkson, 43, filed for divorce from Blackstock, a talent manager, in 2020 after seven years of marriage, and their split was finalized two years later. Although their divorce was acrimonious and the pair have since been embroiled in legal proceedings, sources say Clarkson understands the importance of her children’s relationship with their father.

“The divorce was incredibly difficult for her—it was messy, painful, and made her feel terrible,” the source said. “But she always wanted the kids to have the best possible relationship with their father. She never said a bad word about Brandon to the kids.”

In 2023, Clarkson  opened up about co-parenting  with Blackstock and insisted that her children and their feelings were her top priority.

“I ask my kids every night when we cuddle and put them to bed, ‘Are you happy? And if not, what would make you happier?'” Clarkson shared on Angie Martinez’s IRL podcast . “Especially the last two years… it’s been heartbreaking [but] I want them to be honest so I never say, ‘Oh my God, don’t tell me that,’ but a lot of times they  ‘ll say, ‘I’m just so sad . I wish Mom and Dad were together.’ They’re so honest about it. I’m raising people like that.”

She continued, “I just sat there and thought, ‘I get it. I come from a divorced family too. I get it. It sucks. But we’ll work it out. And we both love you so much.'”

In 2021, Clarkson shared on her talk show that  sharing parenting duties  was “difficult,” but there were things she and Blackstock agreed on.

“It’s hard. … I know that between Brandon and I, it’s just a hard thing because we’re in different places, and we both agree on the main things, but for me personally, it’s a hard thing when you’re not together all the time,” she said, later adding, “As long as you make sure it’s for the kids and their best interests, then we’re both on the same page.”

A family representative announced Blackstock’s death on August 7 in a statement revealing that he had “bravely battled cancer for over three years”.

“We are deeply saddened to announce the passing of Brandon Blackstock,” the statement read. “Brandon bravely battled cancer for over three years. He passed away peacefully, surrounded by his family. We thank you for your condolences and prayers, and ask that you respect the family’s privacy during this incredibly difficult time.”

Blackstock did not publicly share his diagnosis before his death, although Clarkson  revealed he was “sick”  in a statement shared on Wednesday, August 6.

Clarkson wrote on Instagram at the time that she would be postponing her Las Vegas show so she could be “fully present” for her children.

“While I usually keep my personal life private, last year my children’s father became ill and I needed to be there for them,” she wrote in a statement. “I sincerely apologize to everyone who purchased tickets to the show and I am deeply appreciative of your kindness, generosity and understanding.”

The “Stronger” singer  missed several episodes  of her talk show  The Kelly Clarkson Show earlier this year, largely due to Blackstock’s illness, multiple sources told PEOPLE magazine.