St John officers Trudy Taylor and Dorothy Atkins attended Hilal at Castlecliff last year and they give full credit to bystander James Davis, who performed CPR until the ambulance arrived.
"Without that immediate action, it's unlikely we could have brought Hilal back. He did save his life, because minutes are crucial in a situation like that," said Mrs Taylor.
Both officers said it was rare to be called upon to perform cardiac resuscitation on such a young person.
Mrs Atkins said: "It is the first time in 12 years that I have had to perform CPR on someone so young, apart from infants who have stopped breathing."
Paul Francis and Andrew Prescott were in the second ambulance to arrive at the scene. Mr Prescott administered electric shock to Hilal's heart before he was transferred to Whanganui Hospital, where he received further shocks before being airlifted to Starship.
"It was so good to see him after he came back from Starship," said Mrs Taylor. "We don't often get the opportunity to catch up with patients after recovery and it was lovely to see him just being a happy little kid."
Ms Allan said Hilal was placed in an induced coma at Starship.
"He had a hypoxic [lack of oxygen] brain injury when his heart stopped and, when he woke from the induced coma, it wasn't known what his condition would be. He had to relearn how to eat, drink, move his limbs and walk again."
Hilal was fitted with a hybrid defibrillator, which will deliver a shock to his heart if it should stop again.
"Since the original surgery, the device has been repositioned four times, once last year and thrice this year.
"After the first two surgeries, he also had to spend time at a children's rehabilitation centre, practising balance and fine motor skills.
"You would have to have a sharp eye to catch his left-hand fine motor skill control, that's the only visible sign left. That, and the scars on his chest," said Ms Allan.
"We would now like to help the Heart Kids charity, who supports Heart Kids and their families throughout their lives.
"They receive no government funding but are active across the country."
Heart Kids New Zealand communications officer Kit Odlin said the organisation was delighted to be the chosen charity for the Lake Taupo Cycle Challenge. "There are around 12 babies born in New Zealand with a congenital heart defect every week and about 450 open heart surgeries are performed on children - sometimes on babies in their first few days, or even hours, of life.
"Hilal is a very special little boy and it is wonderful that he and Jessica have chosen to support Heart Kids in this way."
To make a pledge to support Hilal visit the website or drop into the Wanganui Chronicle to make a donation.