LONDON (CBS) Cancer patient Harry St. Ledger, 6, says when he's dressed as Spider-Man, he feels brave.
"Because of his webs, because of his muscles?" asked dad Cairan St. Ledger.
"His outfit!" Harry answered.
Harry's parents learned their son had a potentially lethal brain tumor when he went to the doctor with an ear infection that wouldn't go away. He recently underwent radiation therapy at a London hospital-- the only treatment option.
"This is the radiotherapy mask Harry wore during six weeks of radiotherapy. They have to wear a mask because radiotherapy is delivered with pinpoint accuracy," his dad explained of the Spider-Man mask.
When Harry went back to school, his friends dressed as superheroes to honor him.
"I dressed up as Harry because he's my hero," sister Emonie St. Ledger said. "He has been amazing, brave."
Harry and his family have teamed up with the UK charity Brain Tumor Research with a goal of raising $70,000 toward a cure.
"I think it is extraordinarily brave and selfless of Harry and his family at this most difficult time to think about others," said Hugh Adams of Brain Tumor Research UK.
Not all children respond to the radiation, but "Harry Boy," as he's known to his family, says he believes in Spider-Man's superhero powers.
Cairan St. Ledger: Who's braver, Harry or Spider-Man?
Harry St. Ledger: ME!
His parents say they'll need strength as they wait to see what the future will bring.
The American Cancer Society says brain and spinal cord tumors are the second most common cancers in children, after leukemia. They account for about 1 in 4 childhood cancers.