It was on a typical Sunday night a couple of years ago that mother-of-three, Simone, noticed that something wasn't right with her 5-year-old son. As hard as he tried, Hayden couldn't use his left arm to undress for the bath. Simone had noticed earlier in the week that he was slow and clumsy to get in and out of the car, too — even falling out of it at one point.

Following her intuition, Simone took her son to the doctor, who quickly referred them to the Royal Children's Hospital Melbourne. There, a CT scan showed Hayden had a tumour the size of a golf ball on his brain stem.

Even though it's very rare — around 100 Australian children aged under 15 are diagnosed with a malignant brain tumour or spinal cord tumour each year — brain cancer kills more children than any other disease. Only 2 in 10 people diagnosed with brain cancer will survive for more than 5 years.

Childhood cancer is a long road

After years of treatment and rehabilitation, Hayden's tumour has stabilised. But his story continues.

"The childhood cancer journey does not end the day they finish chemo," explains Simone, who now, along with her husband Richard, helps other families affected by childhood cancer. "Once diagnosed, [childhood cancer] changes your life forever. Even though Hayden has been stable for nearly 2 years, every MRI still makes us nervous.

"We live with the trauma resulting from the brain tumour every day. Hayden lives with a left-sided weakness, balance and fatigue issues, and emotionally he can be fragile.

"Mostly, though, he is resilient and finds humour in everything. He is remarkable — as are all the kids who suffer incredibly from this beast of a disease."

How you can help

Here are just a few ways you can support a family living with cancer or serious childhood illness.

• Make specific offers of help rather than your friend having to suggest ideas, advises Redkite (e.g. 'I'll cook some meals that you can freeze' or, 'I can pick up your other children from school').
• Give your friend opportunities to talk. If you're not sure what to say, "I don't know what to say" is fine. It's better than saying something you don't mean or avoiding talking to your friend altogether, according to Canteen.
• Many people mean well but don't appreciate that the cancer journey can be a long one, so offers of help can stop coming after a few months, says Redkite. Do keep checking in on the family — don't go quiet after the initial weeks or months.
• Learn more about the child's type of cancer and what kind of treatments they may undergo on the Cancer Council site, or by calling 13 11 20.
• If you're having trouble explaining cancer to your own children, try the free Camp Quality Kids' Guide to Cancer App — available on the App Store and Google Play.

Know the signs and symptoms of brain cancer

Thankfully, brain cancer in children is rare.

Spotting the signs of a brain tumour early may give children like Hayden a better chance of survival. If you notice that your child has one or more of the symptoms listed here, and it lasts for more than 2 weeks, you should take your child to their GP.

Most of these symptoms are common in children and are unlikely to be caused by a brain tumour, but it's good to get them checked out.

If you're not sure of what to do next, you can use the healthdirect Symptom Checker.