Born in Masterton in 2004, he was 12 when he was diagnosed with a rare cancer known as synovial sarcoma.
He was able to beat it that time and he had been two years cancer free in June 2019.
In December of that year, he was told the cancer had returned and he was given a prognosis of between three and five years.
Knowing his time was limited, Jacob proceeded to make a bucket list of all the things he wanted to do, and packed as much as he could in those two and a half years, from trips to see the whole of New Zealand to seeing the Southern Lights.
But what was more remarkable about Jacob was the lives he touched, evidenced by the number of people who gathered for his farewell at the Hub in Dannevirke on Friday.
Very few of around 400 seats were left empty and more would have watched the service by livestream.
Welsh said he got to know Jacob through his work as a representative of the church and as a member of the board of Totara College.
"He was a special young man."
Jacob at 15, not long after he had been told his cancer had returned. Photo / NZME
Many of Jacob's fellow students came to the service and friends performed an emotional haka as his coffin was being taken out to the hearse which would take him to Palmerston North for a private cremation.
"He had his times of darkness and despair but they were dwarfed by his humour, his positivity and his cheery nature."
Jacob's sense of humour was evident in the way he pranked people and teased his siblings, and in the way he approached his cancer by naming his tumours.
"His overall approach was to treat it as an unwelcome visitor rather than something to be feared or to be dictated by."
Jacob's family said he was an adrenaline junkie who loved the opportunities he had, whether it was flying a jet fighter, driving fast cars or just spending time playing games.
"He treated people how he wanted to be treated."
His instructions for his service showed as much about his nature with the expectation that those who came wore bright colours.
He had also apparently schemed to try to come up with something in his coffin to freak everyone out.
As was Jacob's nature, he also got to have the last word in a message recorded for the service.
He thanked all those who had helped, especially his family and friends, and doctors, and asked people to support his family.
"Please don't [dwell] on me too much, keep moving on with life. Go make a difference.