Celine Dion's sister shares heartbreaking details of her illness

Celine Dion's sister shared heartbreaking details of the singer's disease in an interview.

Speaking to HELLO!,  Claudette said, "The disease is a mystery to doctors and there's very little that can be done to ease her pain."

Claudette said the singer’s family are there to “alleviate her pain” but Celine is fighting tooth and nail to get better from this incurable disease.

“Celine is doing everything to recover. She's a strong woman. It's an illness we know so little about. There are spasms – they're impossible to control.”

“There's little we can do to support her, to alleviate her pain,” remarked the 74-year-old.

Celine’s sister further stated, “We're crossing our fingers that researchers will find a remedy for this awful illness.”

In May, the Canadian singer announced that she was canceling the European stretch of her world tour due to a medical condition that makes it difficult for her to perform.

She said she was diagnosed with a rare neurological disorder called stiff-person syndrome that causes muscle spasms. At the time, the disorder forced her to postpone some European shows on her "Courage World Tour."