Céline Dion's Health Struggles Are 'Heartbreaking' but She Finds 'Light' in Her Sons: Sources (Exclusive)

Céline Dion is finding light in her sons as she navigates her stiff-person syndrome diagnosis.

In this week's issue of PEOPLE, a source tells PEOPLE that the Canadian singer — who recently canceled her concert dates through April 2024 — is "doing everything she can" to get back onstage.

“It’s heartbreaking that she has had to cancel touring but she is suffering mobility and other issues from the disease disrupting her daily life," a music source tells PEOPLE exclusively of Dion, 55.

“She is doing everything she can while working with doctors because she wants to perform,” the source continues. “She has not given up at all. She is hoping to get all of the issues with this disease under control so she can sing again."

The source adds that "singing is her life" and she "loves her audiences": "Seeing this happen is upsetting to her and to everyone around her.”

Another source tells PEOPLE that as she works on her health, her three sons René-Charles, 22, and 12-year-old twins Nelson and Eddy, are a source of joy.

“Her main focuses are always her sons and performing. She is the most selfless and considerate person," says the insider. "Céline just loves her boys so much. They are amazing. They give her all the support and love that she needs."

"They are her light right now," adds the insider.

Dion announced the show cancellations on Thursday and said that she was  "unable to successfully prepare for and perform the remainder" of her tour after her stiff-person syndrome diagnosis.

On Monday, a source told PEOPLE that she's "focusing on her health" and "she couldn’t keep postponing shows — it wasn’t fair to the fans.”

The power ballad queen previously revealed she was diagnosed with stiff-person syndrome, a rare and incurable neurological disease that can cause debilitating muscle spasms, back in December. At the time, she said in an Instagram video that it forced her to postpone and cancel a few upcoming shows.

"I've been dealing with problems with my health for a long time, and it's been really difficult for me to face these challenges and to talk about everything that I've been going through," she wrote.

The Stiff Person Syndrome Foundation notes that Dion's condition affects the central nervous system, specifically the brain and spinal cord. It can leave patients "disabled, wheelchair-bound or bed-ridden, unable to work and care for themselves," per the foundation, which adds that the neurological disease with autoimmune features can include "hyper-rigidity, debilitating pain, chronic anxiety," and muscle spasms "so violent they can dislocate joints and even break bones."

For more on Céline Dion, pick up the latest issue of PEOPLE, on newsstands everywhere Friday.