The 47-year-old publicly mourned the loss of her beloved spouse Rene Angelil on Friday with the couple's three children by her side.
She was part of her sibling's memorial service a day later, but sources tell Entertainment Tonight, grief took its toll on the star, and she was forced to skip another day of mourning in front of the media and fans.
Instead, the Think Twice singer paid her last respects to her 59-year-old brother at the memorial service, held in Salon Charles Rajotte in Repentigny.
Daniel, one of Dion's 13 siblings, lost his battle with cancer on January 16, just two days after Angelil, 73, died of the same disease.
Daniel's funeral took place in Charlemagne, Quebec, where the family was raised, while Angelil was laid to rest on Friday at the Notre-Dame Basilica in Montreal, where Dion and Angelil were married in 1994.
Dion held hands with the couple's twin boys Nelson and Eddy, five, throughout the service, while her eldest son, 14-year-old Rene-Charles, read a moving eulogy to his father.
"Fifteen years is not a long time for a son to get to know his father," he began, before trying to lighten the mood as he talked about sharing his late dad's passion for golf, poker and "smoked meats".
"You left me now with enough good memories of you to share with my younger brothers," he added.
"I'll make sure to pass on what I've learned from you. You are a tough act to follow... but I promise you here that we're all going to live up to your standards."