Van Schalkwyk was raised in South Africa but moved to Christchurch with his family in 1997, Stuff reported.
He returned to South Africa in 2008 and last year travelled to Thailand, training to teach English, taking a job at the Western International School in October last year.
His Auckland-based sister Nina Greeff said on a Givealittle page she set up to fund travel for the family to Cambodia, her brother was "a beautiful human gone too soon".
"There are no words for the pain. A bond that can never be replaced."
Greeff said it was still "so unreal" that her brother was gone.
"My parents and family are currently in South Africa and my husband and I in New Zealand," she wrote at the time.
"Mum and Dad are travelling to Cambodia on [Easter] Monday and my husband and I are hoping to be there too. We all need closure."
So far the page had raised $850.
"My husband and I would like to raise funds to help my parents with any expenses, flights, and anything they may need help with.
"The only thing we could think to do was to reach out through this for anyone who may want to contribute."
Greeff told Stuff the family believed her brother did not realise how sick he was.
"He had a temperature of 42C. The medical report we received from the hospital stated that the cause of death was meningitis."
She said her brother planned to permanently return to Auckland this year to stay with Greeff and her husband John while he looked for work.
"Then suddenly and unexpectedly this awful tragedy happened."
Greeff told Stuff, she and her parents Lochleen and Pieter van Schalkwyk from Durbanville in Cape Town, met with the children her brother taught in Cambodia.
"They were so sweet and kind. We all cried together and they gave us hugs. They called him their giant teacher."
One of them posted on Facebook that she "missed my great teacher very much".