John Nelson called for a sense of perspective and balance about Oxford Court Lifecare, and noted auditing had not revealed serious or systemic problems there.
He said he and his brothers remained supportive of the rest-home, which looked after their mother Connie Nelson, aged 104.
Oxford Court has been on the receiving end of negative publicity relating to allegations about its workplace culture, and Mr Nelson said a "barrage" of people had asked him when his mother would move.
However, she was happy with the care she received.
Mr Nelson is a retired chartered accountant, qualified auditor and a past president of the New Zealand Organisation for Quality.
"The reality is that aged-care facilities in New Zealand are subject to strict monitoring," he said.
"They must be certified by the Ministry of Health, undergo regular independent audits and meet national standards covering safety, medical care, dignity, staffing, infection control and cultural respect."
Mr Nelson said Oxford Court was meeting the standards expected in New Zealand, and the daily care provided to his mother had been competent and compassionate.
"It is important to acknowledge that occasional lapses, causing significant distress for those concerned, can occur in any aged-care facility, but these do not amount to systemic failure."
WorkSafe met the owners of Oxford Court in October after complaints about the rest-home’s management.
A site visit was not required, the company was asked to review policies and it had made progress, a WorkSafe spokesman said last month.
Mr Nelson said if his mother had any complaints, he was sure she would speak up.
His brother Dave Nelson said he visited at least once a week and had not noticed any issues.
Mrs Nelson said she had been at the rest-home for almost 11 years.
"I’m well looked after here," she said.
"The staff are always very helpful to me."
