Even though his life was cut short, his parents have been ensuring their son's legacy will be one that could help change the outcome for other children diagnosed with the terrible disease and save their families from the path the Willses will walk for the rest of their live.

Benny was diagnosed in September 2008 with diffuse intrinsic pontine glioma (DIPG), an aggressive but rare tumour that grows in the brain stem. He lost his battle in September 2009, four months before his fifth birthday.

A year after Benny's death, Mrs Wills and her husband David held the first Benny Wills Gala Dinner to honour him and raised $36,000 for the Sydney Children's Hospital Foundation, which then started The Benny Wills Brain Tumour Research Program

"When we set out to honour our son by raising money for brain tumour research, we had no idea that not only would Sydney Children's Hospital commence a program researching outcomes for brain stem tumours, but that they would also name the program after our son," Mrs Wills said.

She paid tribute to Benny as a bright and chilled boy, while speaking The Canberra Times in the garden that was gifted to him in 2009 by the Canberra community and is now a special place enjoyed by his younger brothers Tommy, 6, and Sam, 2.

The family decided to make the gala dinner an annual event and they have raised more than $200,000 for research into DIPG.

The Willses hope to raise even more money at the fifth annual gala dinner on September 20 at the Southern Cross Club in Woden.

"If we can contribute in even a small way to stopping other families from having to go through this, then to me, that's a pretty amazing thing for our son to leave behind, and from a purely personal perspective it keeps Ben actively a part of our lives and we're still doing something physically for him every year even if he's not here with us anymore," Mrs Wills said.

"It's a chance for hopefully other kids to grow up and have a voice and be something. There's all the obvious things a child never gets to do when they die, but you think, what contribution would that kid have made to the world if he got the chance to grow up."

Meanwhile, Children's Cancer Institute and Sydney Children's Hospital recently announced an international clinical trial

Tickets for the Benny Wills Gala Dinner cost $100 a head and can be purchased at bennywills.org.