She remembered as a child having the sense that her sister was different, but not that she was going to die. Her sister used to giggle, spit up her food and grind her teeth — to this day, Dr. Shapiro can’t bear the sound of grinding — but she was also like a little doll, and Dr. Shapiro loved taking care of her. Her sister’s death, when she was 2, came as a shock. Dr. Shapiro, 11 at the time, went to the wake and cried, but only because she saw everyone around her doing the same.

“We were told she went to heaven,” she recalled. “But I didn’t really have a sense why.”

Everyone in her family seemed to process the grief in different ways. Her father became a deacon in the Catholic Church. “There was no preparation, no explanation about why this happened — it put me on this journey to figure out why,” Dr. Shapiro said, later adding: “I don’t think I would’ve been a doctor without that.”

August: ‘The Solution and the Nightmare’

In the weeks before New York’s law took effect, the Quiĕtus team members found themselves at once ready for the change and also uncertain. For one thing, they didn’t know how many patients they could expect. When New Jersey legalized medical aid in dying in August 2019, only 12 people got prescriptions for the drugs that year; as of 2023, that figure rose to 101 people, 91 of whom used them. Mr. Atkins, the social worker, wondered aloud about the risk of quitting his full-time job. They all channeled their unease in different ways.

Mr. Cogan was a whirlwind of activity, refining the Quiĕtus website, adding a unified color scheme and font (the neutral public sans) to make it look professional, less amateur.

Mr. Atkins had given notice at his hospice job, and he invited a Buddhist monk and a nun friend over to his home to offer a blessing for his new chapter. (The monks were sometimes called to chant for the opening of new businesses, like the nearby H Mart.) Over dinner, the monk and nun talked inquisitively about their thoughts on medical aid in dying, asking how it fit with the Buddhist ideal of causing no suffering, even to a fly.