The Duchess of Cambridge has pledged to plant a sunflower in memory of a boy whose brother raised thousands of pounds for the hospice that cared for him.

Kate spoke to 13-year-old Stuie Delf, who ran a sponsored 5K every day last month to remember his nine-year-old brother Fraser, who died in January.

She was joined by the Duchess of Cornwall in the video call to mark Children’s Hospice Week, as the royal pair carried out their first-ever joint engagement.

“I hear you’ve been doing lots of fundraising, which has been amazing,” Kate told the teenager.

Stuie told the duchesses he was inspired by 100-year-old NHS fundraiser Captain Sir Tom Moore.

Camilla added: “Oh Captain Tom. Captain Tom has done a lot for this country, hasn’t he? He’s inspired so many people. You must be very fit, Stuie.”

The two duchesses spoke to the youngster, his parents Stuart and Carla Delf from Huntingdon, Cambridgeshire, and representatives from Children’s Hospice South West and Helen & Douglas House, both of which have Camilla as patron, and East Anglia Children’s Hospices (Each), of which Kate is patron.

Camilla said in the call last week: “We’d like to thank everybody that works for hospices across the UK for the incredible job you do and allowing families to treasure their moments together.”

They heard how the Each hospice in Milton, near Cambridge, where Fraser spent his final weeks, saw a dramatic drop in fundraising because of the Covid-19 crisis.

Stuie, who was cheered on by his neighbours, set out to raise £500 to fill the gap and to thank staff for helping create the cherished memories he spent at the hospice with Fraser.

“Fraser wasn’t just my brother, he was my best friend,” he said.

He has raised close to £16,000, and with gift aid his total is £18,500, his family said.

The Delfs spent seven weeks living in the hospice with Fraser before he died as a result of Coats plus syndrome, a rare condition that affects multiple organs and causes brain abnormalities.

Kate, 38, asked how the care had been and appeared moved by the family’s story.

Mr Delf, 42, said afterwards: “She said she was going to plant a sunflower in memory of Fraser.

“I’m not sure which Each it’s going to be but at one of the hospices.”

The sunflower has been adopted as the emblem of hospice care, a symbol of joy with the seeds representing patients and the surrounding petals as love, care, and compassion.

Mrs Delf told Kate and Camilla about the kindness of staff who helped her and her husband arrange for a vicar to come and renew their wedding vows in front of Fraser, who had never understood why he was not in their wedding photos.

She said: “Fraser had always looked at our wedding pictures and asked where he was in those.

“And it was our 10th year in the July so we decided, ‘actually let’s do it and renew our vows’.

“And if you’d seen the change in the care floor that those staff had done in 48 hours it didn’t look like a care floor. It was amazing, it really was.”

Kate, who became patron of Each in 2012, praised the “extraordinary” work of children’s hospices.

“Children’s hospices go that extra mile actually and support families like yourselves, I think it’s extraordinary,” she said.

The duchesses were joined on the call by Eddie Farwell, co-founder and chief executive of Children’s Hospice South West, and Clare Periton, chief executive of Helen & Douglas House, and discussed how the pandemic had forced many of the UK’s hospices to change their ways of working.

Mr Farwell, whose two children Kate and Tom both died from a rare degenerative disorder after spending time at Helen House in Oxford in 1991 and 1995, now runs three hospices in south-west England.

He said: “Obviously most of our families are shielding very vulnerable people, young people, and not wanting many of them to venture from their homes.

“So we’ve had to turn our family-based respite model into something else.”

Mr Farwell added: “We’re still open for emergency and end-of-life care, but we’re working in the community, which is something we haven’t done before and which has been very welcomed and it’s been enormously successful.

“And it won’t surprise you to know that we are working virtually as well.”

Ms Periton said: “Some of our families just don’t want to come out of their homes. So actually it’s about putting them first and how we can look after them.

“So all our staff are now wearing fun scrubs – and they look quite, very kind of child-friendly – and PPE.”