The 55-year-old's health deteriorated rapidly and her husband, Evans Mott, agreed to help research suicide methods and assemble a kit with which she could kill herself.
Mrs Mott waited until the birth of a grandchild late last year and spent a final Christmas with her family before making the decision to end her life.
She asked her husband to leave her alone in their Auckland home, and he returned several hours later to find her dead.
Justice Patricia Courtney ruled that the consequences of a conviction for Mr Mott would be out of proportion to the gravity of the offence. But she emphasised her decision was based on the particular circumstances of Mr Mott's case.
"Life's been on hold for nine months," said Mr Mott.
Yesterday was Mrs Mott's birthday. "She's been with us all the time," said Mr Mott. "She was so strong, so brave. Not like me, I'm a big sook."