Heather So thought her daughter Emily was suffering from a bout of car sickness when she complained about feeling unwell.
But when she took her four-year-old for a scan, it revealed she had a deadly form of cancer.
Emily was diagnosed with a fatal paediatric brain cancer called diffuse intrinsic pontine glioma (DIPG).
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Her father, BJ, a doctor, said the period "felt like a nightmare slowly unfolding in front of us".
"At the start, the tumour robbed Emily of her smile, which was heartbreaking to see," he said.
"Eventually, it also took her ability to walk, speak, hear and even swallow."
Life started to change for their "funny, quirky, gentle and brave little girl".
The preschooler endured six weeks of daily radiotherapy, with each session requiring a general anesthetic to help her lie still for the procedure.
"Emily endured the only available treatment for children with DIPG – one round of palliative radiotherapy," Mrs So said.
"And then we waited, enjoying what time we could making special memories together."
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During Emily's final months, the family tried to treasure each moment with their daughter.
"One of Emily's bucket list items was to visit a lighthouse and go to the top, which we were able to make happen," Mrs So said.
Seven months after her diagnosis, Emily died at home at the age of five.
She left behind her parents, her 10-year-old sister Caitlin and her nine-year-old sister Annabelle.
"Words cannot fully describe the pain that comes with losing your own child," Dr So said.
"It is a deep and harrowing grief that no parent should ever have to endure.
"Everywhere she went, she took her favourite toy elephant, Ellie, with her.
"And to this day, we still carry Ellie with us on every family holiday in memory of Emily."
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DIPG is 100 per cent fatal and funding for research into the disease is limited, often leaving families to fundraise themselves.
The couple is now doing everything in their power to make sure no parent ever has to endure a devastating loss like their own.
In honour of Emily, 11 cyclists will travel almost 500 kilometres over six days from Mount Kosciuszko to Wollongong.
All funds raised will go towards an Australian-first clinical trial called Levi's Catch, which aims to provide the first effective treatment for children with the disease.
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The research, launched for the first time outside of the US, is being conducted by doctors at Sydney Children's Hospital in Randwick and will use a child's own immune system to specifically target DIPG.
The process involves CAR-T cells - a type of white blood cell - being taken out of the patient's body in a laboratory, then genetically engineering them to target and attack the deadly cancer.
The immune cells are then infused back into the child, scanning and destroying the harmful cancer cells.
The family has also met with NSW Health Minister Ryan Park to discuss the lack of treatment options available and the potential support the government could provide.
"Despite DIPG being such a deadly and aggressive tumour, the medical treatment for children hasn't changed in more than half a century - since before man walked on the moon," Mrs So said.
"We can't change what's happened to our family, but we can do everything we can to make a difference to other children diagnosed with DIPG."
New South Wales parents Charles and Bridget Poolman are also raising awareness of the disease after they lost their nine-year-old daughter Evie in October 2020.
"We can't just accept that when you're diagnosed with this you're going to die," the couple told Sydney radio station 2GB.
"We need to create solutions and options."
