What is the 20 20 20 method of hard boiling eggs?

As I’ve mentioned my dad’s wife was hospitalized for a time. She fell and hit her head.
She’s home now, and my daughter is there taking care of her 24 hours a day.

Kathy has always been high strung and anxious but it’s a thousand times worse now.
My daughter went to make her a hard boiled egg. She refused the egg because my daughter didn’t use the 20 20 20 method so she did it wrong.
I remember her telling me about the method years and years ago. I’ve never used it so I forgot the steps involved.
And Kathy can’t remember the steps involved, just that it was 20 20 20 (minutes.)

Can you help me release my daughter from this minor hell so we can fix the eggs the right way?