As far as big brothers go, it would be hard to find one braver and more supportive than five-year-old Finley Cripps.

His three-year-old brother Ollie was diagnosed with acute myeloid leukaemia (AML) in June last year.

After months of chemotherapy and numerous hospital stays, the family thought he had overcome the blood cancer, which is difficult to treat, but unfortunately the youngster had a relapse.

He will now have to undergo a bone marrow transplant in February – and it is Finley who will be the donor.

Doctors tested all his siblings, Finley, and twin sisters, Ellie and Evie, one, to see if they were bone marrow matches.

Mum Fiona Cripps, of Archers Park, Sittingbourne, said: “We were very nervous to say the least, as they had informed us that there was a one in four chance that one of the siblings would be a match.”

A couple of weeks later, the results came back that all three were a match.

“The relief was unreal,” Fiona, 26, said.

“Ollie’s consultant and the doctors were astonished as it doesn’t happen.”

Finley was chosen as the doctors’ preference as he is the eldest and the same sex.

Before the transplant, Ollie must go through two more gruelling rounds of chemotherapy.

While getting his usual haircut at Richy’s Barber Shop in Sittingbourne High Street, Finley told one of his favourite barbers, Hannah: “I want to shave my hair off like Ollie”.

Fiona and dad Lee Cripps, 27, agreed that if he could raise £500 for Royal Marsden Hospital in London, where Ollie is being treated, he could have his wish.

An online fundraising page was set up just before Christmas and within days he had smashed his target. A date for his head shave is yet to be set.

Fiona said: “We are so overwhelmed with everyone’s generosity.

"I want to shave my hair off like Ollie" - five-year-old Finley

The Go Fund Me campaign and cash donations have seen Finley’s total approach £1,000 for the Royal Marsden.

Fiona said: “We think as a family it’s so important to support them as they are potentially saving our little boy’s life, because of this we want to be able to give something back.”

The money will go towards a list of toys provided by play therapists at the facility, as well as a coffee machine for the nurses.

Any remaining money will be donated to the Royal Marsden charity.

“We could easily just donate the money to the hospital,” Fiona said.

“But we want to be able to see that we’ve made a difference to the families that use the play room and all the nurses there.”

“We never thought we would raise the amount we have and we are still raising more.”