Wee Oscar, as he's affectionately known to everyone already aware of his fight, is battling against a rare form of childhood cancer called neuroblastoma.
This week, the little lad is undergoing scans to find out if the cancer is still detectable in his system.
It comes as Shaun O'Neill prepares to get on his bike on Saturday morning and begin his challenge in Oscar's name.
"It'll be about 1,400 miles - if I don't take any wrong turns," he told UTV, less than 24 hours ahead of kicking off his cycling trip.
"I start in Newcastle tomorrow morning at about 7.30am ... Once it's done, I'll get the train back up."
I don't get to go home until I've got the cycle done.
Shaun explained how he was inspired by a friend, Baz Devine, who travelled around seven European football stadiums in seven days with a Wee Oscar flag.
"I thought we could keep using football to try to capture people's imaginations and my idea is that I'll take the flag to all the stadiums and get a picture pitch-side to raise awareness," he said.
While Shaun has had to train hard in preparation for his challenge, he knows it'll all be worth it
"For the last four or five months, it's been 300-400 miles every week. It's been bed every night at 8pm, it's been no going out socialising, it's been having a good diet ... It's been difficult," he said.
"I'm going to get a lot of snow and I'm going to get a lot of rain, but I can live with that as long as the wind stays away. I'll be a bit sore by the end, but never mind."
The first stadium Shaun will visit is St James' Park in Newcastle, followed by the Stadium of Light in Sunderland, then over to Manchester for trips to City's Etihad Stadium and United's Old Trafford.
Then it's the DW Stadium in Wigan, Anfield and Goodison Park in Liverpool, Stoke's Britannia Stadium, The Hawthorns in West Bromwich and Villa Park in Birmingham.
Shaun has to head to Wales to take in Swansea's Liberty Stadium, then he's headed to St Mary's Stadium in Southampton and Reading's Madejski Stadium, before making his way to London.
There, he'll take in Loftus Road, Craven Cottage, Stamford Bridge, Upton Park, White Hart Lane, and the Emirates, before heading to his final destination - Norwich and Carrow Road.
In the meantime, Wee Oscar is facing a wait to find out the results of his scans after a tough time.
Late last year, a gruelling trip to the USA - where Oscar could have received potentially life-saving treatment - ended in disappointment, when he suffered health complications.
But efforts to help with the cost of medical bills and to raise awareness of the Neuroblastoma Children's Cancer Alliance are ongoing - complete with the backing of a host of celebrities.
On Monday, fearless Oscar showed off his fighting spirit as he joined professional boxers to launch Belfast City Hall's first ever fight night to raise funds for the Oscar Knox Appeal.
Follow Shaun O'Neill's cycle challenge on Facebook or Twitter (@oneill_shaun / @oscarsflag).