Hess (50) and his adventuring "soulmate and friend" Wolfgang Maier (58) died in an avalanche on Mt Hicks near Mt Cook on Wednesday.
The men were guiding Jo Morgan, the wife of economist and philanthropist Gareth Morgan, who survived.
Hess' brother Jochen Hess told the New Zealand Herald tonight he had to break the news to Hess' St John colleagues in Alexandra.
"He was rostered for this weekend ... I had to call them and say he's not coming."
St John couldn't be contacted for comment tonight, but Jochen Hess said his brother had a strong sense of service.
"He always was of the opinion that he needed to give back to the community."
His brother, a trained baker and pastry chef who came to New Zealand from Germany after getting the travel bug while working on cruise ships, was also involved in search and rescue in the mountains where he died.
"He was with the helicopter team at Mt Cook and saved lives ... he was in the helicopter himself when people had died in avalanches, in the mountains."
Hess had also worked for the Australian Antarctic Division in "safety compliance" and before his death split his time between New Zealand and Germany.
He met Maier, his "soulmate and friend" through the mountaineering community at Lake Tekapo and there was some comfort that they had died together, Jochen Hess said.
Family were always "sort of prepared" for his brother's death, he said.
"We knew what he was doing. So, it comes hard, but we knew that his profession you expose yourself to certain risks. So we sort of prepared, because that's how mountaineering goes."
