He was in the clear for two and a half years when a week before Christmas, doctors found it had come back.
With medical staff saying there was only a 10 per cent chance of survival and palliative care would be an option, the Cokers quickly got to work to tick things off Jacob's bucket list.
The family decided to take advantage of a lake house offered by the Child Cancer Foundation in Taupō for a holiday.
Facebook page Gabby's Starlit Hope, a not-for-profit charity that helps children with cancer do the things they love, put the call out for help yesterday.
Initially, the post was just asking for a Taupō photographer to take photos for what could be one of the family's last holiday in the lakeside town.
The charity was started by 13-year-old Gabby Devine, who had bone cancer and used to do acts of kindness for other children in the hospital to get her mind off her illness.
Devine died in 2015, but her parents knew they had to continue their daughter's legacy.
Within hours, Devine's mother Sarah had received offers including six photography packs, Huka Jet rides, a Lake Taupō fishing charter experience, grocery hampers and restaurant and cafe meals on the house the whole week they were there.
Not only that, but more than $1000 was donated so Coker could go both parasailing and skydiving while they were there.
"It is such a beautiful act of community," she said.
Sarah had spent hours filing through email offers this morning and last night for the family.
"It is going to be a really fun time for them, they can forget what they are going through for a week."
Coker's mother Amanda said the family were "absolutely speechless and had no words".
They were blown away by how kind the community had been and Jacob could not believe what was happening, she said.