On Wednesday, his mother, Marie Lambalot Greany, said he “had so much left to give this world.”

“And I don’t think we’ll ever, ever know the reason why he was taken so soon,” she said. “He obviously needed to be somewhere else. And someday, hopefully, we can understand.”

Greany grew up in Mattapoisett with his parents and younger sister, Grace. He went to high school at Tabor Academy in Marion. A high academic achiever, Greany set his mind to attending Northeastern University, making it the only college he applied to.

He excelled there, receiving a bachelor’s degree in cellular and molecular biology in 2021, followed by a master’s degree in bioinformatics enterprise in 2022. For the past two years, he worked at the Hayden Consulting Group, a Boston-based health care consulting firm.

“He was doing what he loved, researching and trying to make the world better,” his mother said. ”We had this family saying that with his brains and everything about him, he was meant to do great things in this world."

On Sunday, Greany was leaving his girlfriend’s home and walking a few blocks to his apartment, where he planned to watch soccer with some friends, his mother said. He stopped at a Dunkin’ coffee shop, which he considered his favorite, and was talking with a childhood friend about an upcoming soccer game during the walk, she said.

When he didn’t return home, his friends became concerned. After they saw a social media posting about a car crash in Andrew Square, they checked his location app. His phone was in the same spot as the crash, his mother said.

“He didn’t suffer,” his mother said. ”That’s all we could have hoped for."

Boston police and the Suffolk district attorney’s office are investigating the crash.

Lambalot Greany said the family asked investigators not to contact them while they plan the funeral services and begin to learn what it will be like to live without him.

“Every minute of the last three days feels like it’s been forever, and it’s still shocking that it’s only Wednesday,” Lambalot Greany said during an interview while her husband, Scott M. Greany, listened on. “Every day we wake up and we say, ‘We can’t, we can’t,’ you know, get up. But we do.“

Lambalot Greany said they have been buoyed by the affection and love his friends held for their son, and they have listened intently as they learned more about the life he has been living in Boston since leaving home in 2016.

“We have had a lot of people in and out of the house, a lot of his friends and his roommates, and we’ve just been talking about the memories of him,” she said. “We’re finally able to look at some pictures and listen to the stories that they all had shared with us.”

Noah Greany was a lifelong Red Sox fan, attending his first game when he was about 3 years old, his mother said.

After talking with his co-workers about how they could honor their friend, his sister, Grace Greany, suggested that donations in his name should be made to the Jimmy Fund, a charity the Red Sox partner with, Lambalot Greany said.

She recalled that when her sometimes distracted son went to Northeastern, she and her husband worried about him crossing the Green Line tracks that run by the campus.

“You know, smart kids with no common sense? My husband and I, our nightmare was that he was going to cross those train tracks and not look. But he survived his years at Northeastern,‘’ she said. ”It was just some freak accident on a Sunday that he died that way. Our worst nightmare. Crossing the street in Boston. In a crosswalk. Like we taught him. From a young age.”

Jeremiah Manion of the Globe staff contributed to this report.

John R. Ellement can be reached at john.ellement@globe.com. Follow him @JREbosglobe.