TMZ reports the news comes less than 24 hours after the death of Celine's husband, Réné Angélil, who also died of cancer.
Daniel, 59, has been fighting brain, tongue and throat cancer in Céline's native Montreal according to his sister, Claudette. He's surrounded by family, including their 89-year-old mother, but it's so bad the family doesn't think he'll make it through another week.
Réné also died of throat cancer.
Daniel's health crisis was first reported by Journal de Montreal.
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