Not long after, in the lead-up to Anzac Day, Waipukurau and Districts RSA president Janet Castell also happened to come across Mr Sweetapple's memorial site, in the public area of the cemetery and not in the section reserved for servicemen.
Janet was laying poppies and sprigs of lavender on soldiers' graves while also researching servicemen to be honoured at the Field of Remembrance service, which the local RSA has held the evening before Anzac Day since 2015.
"So we did manage to place a poppy for him the day before Anzac Day," said Janet, though she confessed that Mr Sweetapple was unknown to the local RSA before this year.
"It's an interesting case. He enlisted in Napier but he's not listed there, he's certainly not on the Hastings Cenotaph, and he's not listed on any cenotaph in CHB.
"It's only now that we know his history, how he died and where he served."
Janet said research revealed that after enlisting on May 30, 1916 - 101 years ago - Mr Sweetapple arrived in England in November 1916 with the New Zealand Expeditionary Force's 17th Reinforcements
Originally posted to B Company, 5th Reserve Battalion, New Zealand Rifle Brigade, he was then posted to the newly formed 4th NZ Brigade on March 30, 1917.
On May 12, 1917, the rifleman was promoted to lance corporal and on May 28 he departed for France and the Western Front as a member of 9 Hawke's Bay Company, 3rd Battalion, Wellington Infantry Regiment.
In October that year, all three battalions of the Wellington Infantry Regiment were involved in the first battle of Passchendaele and though the attack was a success, the Hawke's Bay company suffered a platoon's worth of casualties.
The resulting lack of manpower meant 4th Brigade and 3rd Battalion disbanded in February 1918, and Mr Sweetapple, by now a corporal, was transferred back to Rifle Brigade where he was posted to D Company, 4th Battalion.
After marching to Ypres, 4 Battalion was "badly knocked about" by German shelling in March. They moved to Amiens and on the night of March 27, 1918, marched to Hedauville to relieve a Wellington battalion under attack from German forces.
Mr Sweetapple's battalion was given orders to attack the Germans at 11.30am on March 28.
Fighting continued to March 31, and he was killed in action at some point.
His battalion recorded 53 casualties and 144 wounded over the four days of battle and though the exact date of his death is unknown, Mr Sweetapple's death is officially recorded as March 30, suggesting he was killed in the final two days of fighting.
He has no known grave and is commemorated on the New Zealand Memorial in Grevillers British Cemetery, west of Bapaume in France.
Mr Sweetapple's memorial headstone is part of large family plot and is next to those of his brother and father, who have different surnames, with all three dying within 20 months of each other.
His brother, Charles Henry Holmes, died at Waipukurau Hospital of pneumonia in November 1918 at 33, while his father, William Sweetapple (Holmes), died in November 1919 at sea at 57.
Janet explained that Mr Sweetapple's parents, William and Anne, changed their names from Holmes to Sweetapple, the name of their relatives in New Zealand, after arriving from Portsmouth in England in the early 1880s.
Janet said the family lived in Awatoto so it appeared that the mother, Anne, who died in 1947 and was buried at Tikokino under the surname of Holmes, erected the memorial headstones after moving to CHB following her husband's death in 1919.
Janet said the confusing switch of surnames might explain the state of Mr Sweetapple's memorial site, the upkeep of which was the responsibility of his family.
"No one has been near the grave for quite some time, obviously, but families move away, they forget - it happens.
"There are probably people around here who don't even know they are related to him," she said.
"Or, the family may have chosen to let him rest in peace, which you've got to respect."
Though the RSA had no specific fund to help families repair soldiers' graves, Janet said if any family members wanted to come forward she could try to help find them some financial assistance.
"It's not normally something we would get involved with, however the Department of Veterans Affairs may be able to come to the party to assist," she said.
Even though he did not enlist in Waipukurau, Janet said Mr Sweetapple would be included in next year's Field of Remembrance ceremony, which would be dedicated to the CHB soldiers who died in 1918 during World War I.