Roser has an unshakable belief that everybody who knew Joshua loved him.
"He was an amazing fella, he was about to start his apprenticeship," when the accident occurred, Roser said.
"He had just been accepted a few weeks ago, he had already done preliminary courses at EIT. He was a clever kid, but never blew his own horn."
Joshua came to Hawke's Bay from Australia when he was four and a half years-old.
"His Mum is a Kiwi. They were living in Perth. She came to Hawke's Bay to look after family, along with Josh and his older brother Alex," he said.
Growing up in Hawke's Bay Joshua attended Nelson Park School and Napier Boys' High, Roser said.
"Joshua was a little firebrand, he was a clown and a handsome young fella," he said.
"He had a heap of friends and they are just broken. Anyone who met him, never forgot him.
"He was a kind kid, with a big heart and fiercely protective. He had an old head on young shoulders."
A celebration of Josh's life was held at Beth Shan Chapel, Napier, on Saturday.
He was farewelled by his workmates with an "unexpected, but incredibly moving" haka, Roser said.
"The haka was done at the end as we carried Joshy to the hearse," he said.
"It was the most, incredibly moving thing. I have never felt anything like it.
"He was a bloody good mate to all his friends."
In Joshua's memory his extended family and friends have organised two masses for him in Columbus, Ohio, Roser said.
"You accept what's happened, Josh had an energy bigger than him," he said.
"Joy comes over you when you bring him to mind."