Céline Dion Says Her Sons Fuel Her to Fight Stiff-Person Syndrome

(People) – As she navigated grief and severe health struggles over the years, Céline Dion moved fans around the world with her unrelenting courage and resilience.

On her most difficult days, the music superstar — who was diagnosed with the rare autoimmune and neurological disorder stiff-person syndrome in August 2022 nearly six years after her husband, René Angélil, died from throat cancer — tells PEOPLE exclusively in its latest cover story (on stands Friday, June 14) that she finds strength in, and for, her three sons.

While Dion, who’s mom to René-Charles, 23, and 13-year-old twins Nelson and Eddy, had been battling mysterious health struggles beginning in the mid-2000s, her symptoms (including excruciating muscle spasms, difficulty walking and breathing) dramatically worsened in the years ahead of her SPS diagnosis.

“I barely could walk at one point, and I was missing very much living. My kids started to notice. I was like, ‘OK, they already lost a parent. I don’t want them to be scared,'” says Dion, 56, who lifts the veil on her journey in a Prime Video documentary, I Am: Celine Dion (streaming globally June 25), directed by Academy Award-nominated director Irene Taylor. “I let them know, ‘You lost your dad, [but] mom has a condition and it’s different. I’m not going to die. It’s something that I’m going to learn to live with.”

Dion will also be opening up about her health battle in a sit-down interview with Hoda Kotb for an NBC News primetime special, airing Tuesday, June 11 at 10 p.m. EST.

“I did not take the time — I should have stopped, take the time to figure it out,” she told Kotb (in a preview that aired on Today). “My husband as well was fighting for his own life. I had to raise my kids, I had to hide. I had to try to be a hero.”