Larsen Roberts, from Nottingham, is currently being treated at Queens Medical Centre Children's Hospital for a optic pathway glioma, a slow-growing tumour.
Wanting to raise money for the hospital he has taken on 26 slides today, Saturday, April 13, and has so far raised more than £2,600.
Starting at Center Parcs, in Sherwood Forest, he then heading to other parks including White Post Farm in Farnsfield.
A White Post Farm spokesman said: "He wanted to do something special to raise money for the ward he is being treated by; what better way to raise money than to do a 'Slideathon'.
"Thank you for letting White Post Farm be part of your challenge Larsen, you are a true superhero."