My mother has vascular dementia. Her memory of people and places long past is sharp, but her geriatrician tells me: “Your mother’s brain cannot make new memories.” I’d never heard it expressed like that before. It was helpful and freeing. My brother Peter and I had hoped that our mother’s final years would be enjoyable and serene. She deserved it. By most people’s standards, Mum has had more than a few heavy crosses to bear. Her own mother died in childbirth when Mum was 18 months old. She had only been married eight years when her husband had a cerebral berry aneurysm and dropped dead. She was left a 32-year-old widow. Peter was seven. Our sister Tracey was five. I was two.

Mum never remarried. She never seriously looked for another husband. “I was a catch, but I had the three of you,” she would joke. In 1988, Tracey had a catastrophic car accident and was rendered a quadriplegic. She was 28. Mum was 56. After she had spent the best part of a year in the spinal unit, Mum nursed Tracey at home for the next 27 years, rising every night at midnight, 3 a.m. and 6 a.m. to turn her daughter. Tracey never got a bed sore.