It is clear his parents still mourn the loss of their cheeky, outdoorsy firstborn, who loved Bear Grylls, cooking French toast and making cupcakes, and visiting the sharks at Kelly Tarltons.
But they say the foundation has been a fitting tribute to their generous son.
"Isaac was extremely selfless," Rebecca said.
"He was always wanting to give things away to people in need. I remember we went through his old clothes to give to the Child Cancer Foundation, and he'd come in with his new boys and toys and say, 'what about these, Mum?'
"He loved sharks, and wanted to write to John Key to try and get people to stop killing sharks and dolphins - that's what he was like.
"To be able to give to others in his memory feels amazing."
Rebecca and Matt, who moved to Featherston four months ago, were living in Auckland when Isaac was diagnosed with non-Hodgkin's lymphoma in December 2013.
He was rushed into surgery, as as tumour discovered in his sinuses had spread, cracking his skull and causing brain fluid to leak.
Afterwards, he began an intensive course in chemotherapy, shrinking the tumour.
"He was in hospital having treatment, and kept telling all these silly jokes and was jumping on the bed," Rebecca said.
"The doctors told us he had a good chance of pulling through."
But, a few short months later, Isaac contracted mucor, a rare fungal infection spread by rotting vegetation.
Rebecca and Matt took him into Starship where, with his immune system compromised by the cancer, he went downhill fast -- struggling to breathe from pneumonia in his left lung, having seizures and slipping in and out of consciousness.
To add to his parents' pain, Rebecca had an ectopic pregnancy the morning of Isaac's death -- and had to switch off Isaac's life support while still hooked up to an IV herself.
Isaac was buried on April 12, his birthday.
Not long afterwards, his parents started the foundation, and began arranging for fruit baskets to be delivered to the oncology ward at Starship -- inspired by Isaac's love of fruit and vegetables.
"While he was in treatment, Isaac asked if he could have an apple, and we couldn't find one anywhere in the hospital," Rebecca said.
"We thought it would be nice to have fruit available, as a lot of the food the kids and parents get is quite starchy."
They also started bringing small gift bags of marbles -- one of Isaac's favourite things -- to children having treatment over Christmas.
With extra funding, Rebecca and Matt also hope to offer hand and foot castings for parents whose child has passed away, artistic programmes for grieving siblings, memorial gardens and to raise awareness of child loss -- something which has become a taboo subject.
"It's actually not that unusual for children to die, but it's something no-one wants to talk about," Matt said.
"People were telling us, 'oh, it's been six months, mate, shouldn't you be over it?'
"People would like to think they can ignore the death of a child, but their parents can't."
As a Christmas fundraiser, Rebecca and Matt have designed a cookbook, called "That's Actually Quite Nice, Mum".
It features recipes supplied by child cancer parents, members of the police and fire service, and celebrity chefs Annabel Langbein, Michael van der Elzen and Michael Meredith have contributed too.
"Isaac loved cooking -- we used to watch Masterchef together and we ended up with this little Masterchef judging us.
"We made him a meal one night, and the review was 'that's actually quite nice, Mum.'"
Rebecca and Matt, who will welcome Isaac's little sister in January, say the foundation has helped the grieving process.
"It hurts to think I won't get to see him go to high school, have his first girlfriend, graduate and go on his OE," Rebecca said.
"But this keeps him alive -- and what parent doesn't want to share their child with the world?"
For more information about the Isaac Shenton Foundation, or the cookbooks, go to www.facebook.com/IsaacShentonFoundation.
