Kennedy, a self-proclaimed "Four Square guy" after owning a store in Taranaki for six years, said the offer of personal and professional help was a "no brainer" for a store with employees in need of help.
"It was something we could do to provide certainty for them all as they have bills to pay and family to care for," he said.
"Graham and Rachel are quality people who put 100 per cent into their business and deserve nothing less."
Kennedy said a man with a mortgage and a young child was the first to make contact over the offer.
Wray said thanked Kennedy for his quick response and thanked the wider community.
"He was straight on the phone that morning and has been great," he said.
"But I also want to thank all the emergency staff and first responders. Thanks for the thoughts and support for the Waipawa community and the whole CHB community."
A firefighter suffered steam burns trying to extinguish the fire and was taken to Hawke's Bay Hospital in a moderate condition.
A Hawke's Bay District Health Board spokeswoman said the man in his 30s was treated and discharged on Sunday. Another person was also treated at the scene.
Resident and former Four Square Waipawa employee Gina Hill, who witnessed the fire, said she will always have fond memories of the long-standing site.
"Honestly it was heartbreaking to watch as I have lived here all my life," she said.
Hill said she remembered the site as a PGG Wrightson building, a New World and then Four Square, where she worked for a year.
"Graham and Rachel are wonderful people and I have fond memories," she added. "They were good bosses and the staff were happy, friendly and helpful."
Central Hawke's Bay Mayor Alex Walker said the supermarket was at "the heart of the community".
"We are already working closely with our Ministry of Social Development partners to understand what wider considerations and impacts may also arise for the wider community," she said.
Waipawa, the second-largest town in Central Hawke's Bay, has a population of 2250 and a median average age of 43.3 - compared with 37.4 years nationally.
Waipawa Butchery owner Duncan Smith said the company would deliver to the town's elderly free starting on Monday, for as long as required.
The fire is not being treated as suspicious, but is being investigated by specialist fire and emergency investigators.
Kennedy said it also highlighted the emotions and struggles of running a small business.
"Risk is an inherent part of business and fire is certainly something we worry about and practise for with drills and training," he said. "It's something all business owners dread, but you can't dwell on it.
"We understand how important Four Square is to its community and we will be doing everything required to look after Graham and Rachel, their team and their community while they make plans for the rebuild. Helping a mate in trouble is a pretty straightforward decision."