John Ryan, 48, will complete a 50km indoor triathlon at the town’s Inspire gym on July 15. He will row 10km, cycle 30km and run 10km – all in one day.
He is raising funds for the charity Brain Tumour Research in memory of 13-year-old George Fox – known as Gorgeous George – who died in April, just 12 months after being diagnosed with glioblastoma multiforme – an aggressive brain tumour.
The electrical engineer is a long term friend of George’s mum Louise.
He said: “I’d wanted to get involved before George passed away to add to their GoFundMe page, but unfortunately he deteriorated very quickly which is why I’m doing this now.
"I can do each of the triathlon things individually but doing all three in a day is going to be a challenge, but I’m up for it.
"Louise asked me to do it for Brain Tumour Research so I’m honouring her wish.”
Before he died, George of Barton-le-Clay, had multiple brain operations and underwent numerous bouts of chemotherapy and radiotherapy.
His parents set up a GoFundMe and George travelled to Germany and America for treatment. Sadly he was unable to take part in a planned clinical trial in Los Angeles after his conditioned worsened on the flight out.
His stay in intensive care in America racked up medical bills of hundreds of thousands of dollars, covered in part by generous donations made through the crowdfunding page.
Following George’s diagnosis, he and his family became passionate supporters of Brain Tumour Research.
John said: “Let’s hope George didn’t die in vain. Anything I can do to support research into brain tumours and stop even one more family from having to go through this has got to be a good thing.”
Charity spokesperson Charlie Allsebrook said: “George’s story is a tragic one and a stark reminder of the fact brain tumours kill more children and adults under the age of 40 than any other cancer.
"Yet, historically, just one per cent of the national spend on cancer research has been allocated to this devastating disease.”