They may just be starting out in life, but they still know the importance of helping a friend in need.
And that's why six-year-old Noah Harris and his sister Ellie, two, have decided to brave a 4.5mi walk along the north Norfolk coast from Cromer to Sheringham for charity.
Noah is best friends with five-year-old Izzy Deeba, sister of Harry Deeba, two, who has stage four neuroblastoma.
Noah and Ellie's parents Rebecca and Adrian Harris, from Cringleford, will be joining them on the walk, which aims to raise as much money as possible so Harry can fly to the US for potentially lifesaving treatment.
Mrs Harris said the families had a strong connection and they wanted to do everything they could to help little Harry.
She said: 'I went to school with Carly and her partner Ali - Harry's parents - and we were all good friends.
'Since having children we've become very close friends often having days out together, until poor Harry got poorly last January.
'Noah is four months older than Harry's big sister Isobel and Ellie is 10 days older than Harry. They've all grown up together.'
'Adrian, who will also be doing the walk as well, is fighting his own cancer battle, he had his voice box out earlier this year and is currently in week two of his radiotherapy treatment.'
Other fundraising events taking place for Harry include a superhero walk through Norwich city centre, football match between police and firemen and a sky dive in Beccles.
The youngster was diagnosed with a high-risk neuroblastma - a particularly aggressive childhood cancer - at Addenbrooke's Hospital in Cambridge in January last year. Almost 50pc of children diagnosed relapse at some point, and when that happens, fewer than one in 10 survive.
Harry's family are hoping to raise £239,000 to travel to New York for treatment that could stop the cancer returning.
The Harris's have so far raised more than £150 towards their £250 target, and Mrs Harris is also planning to do a fundraising run for the cause.
To donate to Noah and Ellie's fundraising walk, which will take place on Saturday, April 20, visit www.justgiving.com/fundraising/rebecca-howes3.
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