Claire Lloyd came across the HeadSmart website, which lists the most common signs of childhood brain tumours, after her nine-year-old son Jack had been vomiting regularly during the day for more than a week.
When anti-sickness medication prescribed by the GP made no difference, Claire typed 'child with persistent vomiting' into Google.
Her search led her immediately to HeadSmart, which revealed that vomiting with no other obvious symptoms of illness could be caused by a brain tumour.
Claire and her husband Peter, from New Addington in south London, agreed they would speak to the GP the following morning about what they had read.
But two hours later, Jack began to complain for the first time of severe head and neck pain – another symptom listed on the HeadSmart website.
Jack's parents took him to the Princess Royal University Hospital in Bromley and told staff what they had discovered on the HeadSmart website.
They took Jack’s history and within an hour he was given a CT scan. Our world fell apart an hour later, when we were told Jack had a brain tumour. No words can describe the feelings of dread, fear, terror and disbelief that this is happening to your child.- Claire, Jack's mum
Jack was transferred to King's College Hospital in London where an MRI scan revealed a rare pineal tumour in the centre of his brain, causing a potentially life-threatening build-up of fluid.
He had emergency surgery later that day to reduce the swelling and three weeks later, on October 14 last year, underwent a 12-hour operation to remove as much of the tumour as possible.
Three months later, Jack – who also has autism and Type 1 diabetes – is recovering well.
Claire said: "We are so thankful that we found HeadSmart that day. Having that information was vital in getting Jack the care he needed quickly. It played a huge part in saving his life."