Bev has had dementia for up to three years, but it has only been severe for about a year, her husband, John, says.
The couple did not want their last name used.
This week is Alzheimers New Zealand's awareness and appeal week.
The organisation predicts that by 2026, the number of people in New Zealand with dementia will have doubled.
John said one of the hardest things about having dementia was the reaction of family, who sometimes seemed "flabbergasted" and did not know what to say.
Between them, John (85) and Bev (76) have 11 children, and had "lost count" of their grandchildren.
It was good to receive daily phone calls from concerned offspring, John said.
Bev said some days were better than others, but it helped to keep positive.
She suffered memory loss, and sometimes hallucinated, John said.
John had read up on the best foods for people with dementia, with green leafy vegetables and nuts getting the thumbs-up.
It was best to avoid cheese and alcohol.
Support from social service agencies was "marvellous", John said.
