They speak of their hope of finding their much-loved boy who loved the beach, superhero costumes, rugby, cricket, cats and had an obsession for Lego.
Speaking at his Pyes Pa home, Jack's uncle William Spargo, 38, said the family remained as resolute to find Jack today as on the day he disappeared.
And his sister, Jack's mother Karen Spargo, has a simple message for everyone: "Keep looking for our Jack."
Mr Spargo said the family was not giving up.
"We have been looking everyday for 25 days and we will keep looking until we find him. What Karen wants most to tell the world is 'remember our Jack'. Please keep looking ... if you are at the beach, out on a boat, anywhere near the water. Take five minutes to look. That is all we can ask. We all believe we will find him ... and if not us, it will be one of you."
Jack's parents, Karen Spargo and Wayne Dixon, remain camped out at the base of Mauao, waiting for their only son to "come home".
Every morning before daylight, Jack's father Wayne Dixon makes a solitary climb up to the top of Mauao.
"It is the first thing he does on rising. He walks to the top and when the sun rises he stays a while there, looking with his binoculars all around the track, out to the sea," said Mr Spargo.
Karen Spargo visits Shelly Beach every day.
"All the family do. I myself have been going there every day. So has mum [Jack's grandmother]."
A loving, close-knit family, William 38, Karen, 36, and their sister Melony Armstrong, 39, were born and schooled in Tokoroa but have all lived in Tauranga for 20 years.
Mr Spargo lives with his sons Luke, 9, and Matthew, 5. Jack came over to play often with his cousins.
"We are all very close. Me, Karen and mum all live close. If I don't see or speak to them every day it would be every second day. Same with Jack. I would see him all the time. "
Shelly Beach was a regular spot for family outings.
"Jack liked going to the beach ... he would be the first one to put his hand up to go the beach if someone said they were going."
On October 1, when the tragedy happened, Jack would normally have been in daycare.
"But because it was school holidays mum took the day off to take the kids to the beach. The exact same group did the exact same trip to Shelly Beach last school holidays in July."
The group comprised Mr Spargo's mother, Jack's aunty Melony, Melony's daughters Georgia, 12, and Emily, 14, Jack's sister Brooke, 11, and William Spargo's sons Luke 9 and Matthew 5 - and little Jack.
Mr Spargo said the group had been at the area for a while "collecting shells, doing what kids do", when just before midday, they were getting ready to leave when they stopped and turned back to take one last photo.
"Brooke and my boys came up to the grass in front of the picnic bench where mum and Melony were, getting ready to go.
"Georgia, Emily and Jack came up but then went to stand by the rock for one last photo.
"Mum took the photo. It was the last photo."
Just moments later, the tragedy happened.
The photo his grandmother took is the last treasured memory of her grandson.
Mr Spargo said while the family had been boosted immensely and "blown away" by the outpouring of support from the community, there had also been negativity about the incident that they wanted to put straight.
"It has been hurtful for Karen, for us to hear or read online some negative comments, like, 'oh what were they doing by the water'. We want to put that straight. The children were well supervised. They were right in front of my mother and sister Melony, all facing them. Their eyes were right on them.
"There were other people playing on the beach. The children where they were standing were at least 5m from the highest point of the water. The photos that mum has of them show it. This freak wave came out of the blue from the side, reaching another 15m over them," he said.
"Even a strong swimmer would have no chance. Mum and Melony did all they could. They went in immediately and were up to their necks in water. Luckily the girls were thrown in the direction of the rocks. It is no-one's fault. It is an accident. It is hurtful to hear people that don't know us make comments like that. Jack - and all the children - are well cared for and watched. Much loved."
Mr Spargo said the tragedy has not deterred the family from visiting the Mount or made them fear the sea. "We have all been on the beach again since, several times and on Shelly Beach."
It was hard to put into words how the family was feeling, he said. In the first days they ran on adrenalin.
"It didn't seem real ... like the stuff you read about."
Now the hardest thing for the family is accepting that Jack is not there. The family's closeness keeps them strong.
"What has kept us going is each other, and feeding off the determination we all have to find him. We all are there for each other ... We let each other grieve in our different ways."
"Karen is coping as well as can be expected. It is a day-by-day thing ... We are a very big, close family. She is eating, she is sleeping. Anyone who has kids would understand. It is not just that we have lost him, but the fact he is not there."
Jack is Wayne and Karen's only son. Between them they have four daughters, Brooke, 11, Courtney, 17, Hayley, 18, and Jordy, 20.