Ally Parker's five-year-old daughter, Braylynn, was diagnosed with Diffuse Intrinsic Pontine Glioma in December 2017. She was placed in hospice care soon after her diagnosis.
Ally's father, Sean, is also suffering from a neurological disease which has made him terminally-ill.
She had been documenting her daughter's journey on Facebook to raise awareness of Braylynn's condition, as well as raise funds her medical care.
While doing this, she has been sharing some heartbreaking photos of Braylynn in hospital - including one of the little girl and her grandfather, Sean.
The photo, which showed the tragic effects of childhood cancer, quickly went viral across the globe.
The Facebook page was updated on Monday night to inform followers that Braylynn had sadly passed away.
It read:
"She loved Hello Kitty and her birthday was December 10.
"She was a princess with the strength of a warrior and she will NEVER be forgotten.
"We need this cruel disease called DIPG to stop taking our children away from us!"
Braylynn's story went viral last week after one of the photos Ally shared on the Facebook page struck a chord with social media users.
The picture depicted Braylynn in her hospital bed with her granddad, Sean, sitting beside her and crying.
