Harley Whitford, eight, has already smashed his original target and he wants to raise even more for The Sick Children’s Trust and the Leeds Heart Surgery Fund.
His mum, 26-year-old Racheal Wall, is good friends with Leanne Shirt - the mum of young Hope who has had a number of open heart surgeries to keep her alive - which is why Harley has decided to raise money for those charities.
Racheal said: “Harley’s going to be walking 20 miles from Barnsley Hospital to Leeds General Infirmary in fancy dress to help raise money for those who have helped Hope.
“Leanne and Mike’s son is going to be doing it as well on August 1 with Harley so he’s really looking forward to it.
“He’s quite happy with how everything has gone - he’s going out everyday walking around six miles so he can train for it.
“He’s raised £300 up to now so he’s smashed his goal of £100 - I’m so proud of him.”
To donate to the fundraiser, visit Hope’s Journey on Facebook.