When Tina Smith, 40, first noticed her five-year-old son Alfie Smith's right eye was protruding, she thought he'd just banged it while messing about with his siblings Liam Carey, 21 Lewis Carey, 19 and Jordan Carey, 17.
But, as the swelling worsened, so did her concern.
After a long stint of being passed around various different doctors, the family were finally given a diagnosis at Poole Hospital in Dorset.
Alfie, who was four at the time, was told he had a grade 1 meningioma tumour, which had started in the front of his brain and gradually spread to behind his eye.
"Everyone had been telling me it was nothing to worry about, but all this time, the tumour had been growing and growing," said Smith.
One month after Smith first noticed Alfie's eye in December 2014, she was getting him dressed one morning and noticed the swelling had worsened.
Just to be on the safe side, she took him to his GP, who prescribed him eye drops.
But, as the weeks passed, the inflammation grew more and more prominent.
In April 2015, Alfie was taken to an opticians to be checked over.
There, he was referred to hospital for a more thorough examination – but was told the wait would be 13 to 14 weeks.
"It was frustrating," said Smith.
"Everyone kept reassuring us that they didn't think it was anything to worry about, but you could clearly see there was a problem with Alfie's eye."
With little else to do but wait for her son's hospital appointment, Smith took to the internet for advice.
"When I typed in Alfie's symptoms, a lot of pages about tumours and cancers came up, but I didn't think they applied to us because everyone had been so sure we had nothing to worry about," she said.
"I was looking for a simple answer."
Eventually, the day of Alfie's appointment came round and, after being examined at Dorchester Children's Clinic, he was referred to Poole Hospital for an MRI scan the following week.
There, they were finally given the diagnosis.
A meningioma is a tumour that arises from a layer of tissue (the meninges) that covers the brain and spine. A grade one means the tumour "grows slowly".
Doctors recommended that Alfie should be given surgery as soon as possible, but warned that it was unlikely they'd be able to completely remove the tumour, as part of it had wrapped round his bones.
In July 2015, Alfie underwent an 11-hour operation, during which surgeons cut away as much of the tumour that they could.
"We knew they'd never be able to get all of it," said Smith. "But we were told that it was slow growing, so we hoped it would be years before it returned."
The Smith family's hopes were dashed once again when Alfie's tumour began to grow back in just a few months.
Despite facing such an ordeal so early in life, the youngster has kept a brave attitude.
His mum added: "Because he's too young to understand exactly what cancer means, we tell Alfie he has a 'poorly eye' and that doctors are trying to fix it.
"But visually, he can see his face is swollen and he knows there's something wrong."
In June 2016, Alfie underwent another bout of surgery and, in July, he will fly to Jacksonville in Florida for pioneering proton beam therapy.
Smith worked tirelessly to raise the £4,000 needed to help with living costs while they're in the States having the treatment – a form of radiation therapy – which works by beaming protons towards cancer cells.
Protons can be controlled to release much of their energy directly into a tumour, meaning less surrounding healthy cells are affected.
However, the procedure is not without its risks.
"Because of the position of the tumour, it's possible Alfie's development could be affected, or he could lose his sight," explained Smith.
"It's terrifying hearing that, but what's the alternative?
"I can't just sit back and leave his tumour to grow. It'll take his life."