Kind-hearted Arry West, who is 44, will get on his bike for the epic Mountain Mayhem challenge on June 22 and 23 in aid of research into the condition ME (Myalgic Encephalomyelitis).
Arry and his wife Teresa are friends of teen Alex Woodvine, of Newport, who's life changed drastically, aged 11, when he was diagnosed with the illness.
Towards the end of 2014 Alex was forced to leave school due to the effects of the symptoms which include tiredness, severe cognitive impairment, sensory issues, sleep and gastric problems.
As a result he became housebound and then eventually bed bound.
Before he became ill Alex was a member of his local scouts and archery club and he also also had weekly ice skating and guitar lessons and loved to walk the family dog.
However, due to the life changing condition he now relies on a stairlift and powered wheelchair to move around safely.
Alex's mother Kathryn said she was heartbroken to watch her son suffer constantly with no respite.
"He is never symptom free," she said. "Not even for a minute. This has been his life for the last five years."
Arry, of Telford, heard about Alex and has decided to try and make a difference.
"I was quite nervous to meet Alex. I told him I was riding for kids like him, he was really chuffed. It was a big eye-opener and made me think how little people know about the illness," Arry said.
He hopes to raise £1,000 and has so far attracted £740 given by 33 donors.
He will cycle off-road across various terrain at the event due to be held, in Marston Lodge, Northamptonshire, and hopes the weather will be kind to him.
He also said it was important for him not to hit a mental wall during the endurance challenge.
"I am praying for good weather and conditions. It will already be a tough challenge without the rain. I am really grateful for the donations, people have been so, so generous.
"Knowing that I am doing this for others will really push me on. I have something to drive for and work towards and I will do my best to get it done," he added.
The proceeds from his bike ride will go to the charity Invest in ME Research which funds research into the condition.
Kathryn said: "We are hugely grateful that Arry has chosen to support Invest in M.E Research while doing the Mountain Mayhem challenge, and it would be amazing if lots of money could be raised to support Arry."
Also known as chronic fatigue syndrome ME affects just over 250,000 people.
To support Arry's fundraising effort visit www.justgiving.com/fundraising/wwwinvestinmeorg.