Steve Mongeau remembers being in the car with his sister, Kathy, while visiting their parents one Christmas.

“I realized she was dealing with some challenges. But I never thought to ask her if she was thinking of hurting herself or considering suicide. It never crossed my mind.’’ Mongeau said.

“Two weeks later, she ended her life.’’ Kathy was 39.

“If I knew then what I know now, I would have asked more questions,’’ he said.

Mongeau later learned of the suicide prevention group Samaritans when he got a donation request in the mail.

“I didn’t know such an organization existed,’’ he said. He went to a breakfast event and thought “This is something I should get more involved with.’’

He became a volunteer, then a member of the board of directors, including two years as chairman.

After a long career in sales and corporate leadership, Mongeau, 60, of Chelmsford — who studied social work at Cornell — became executive director of the Samaritans in January 2015.

“I just feel like I am supposed to be here,’’ he said. “No other work has been more rewarding.’’

The statewide group has a 24-seven hot line (887-870-4673), staffed by 250 volunteers.

“We’re one of the first crisis centers to take texts,’’ Mongeau said. “It’s the preferred method of communication.’’

While suicide is often related to depression, it sometimes results from just a short stretch of feeling hopeless.

“People are in a tunnel and struggling to find the light,’’ Mongeau said. “We validate their feelings and talk it out. Our hope is to get them through the moment so they can look forward to the next moment.’’

The organization also reaches out to family and friends left behind.

“It’s a complex grieving process,’’ Mongeau said. “Some of your closest friends don’t know how to talk to you.

“Suicide is preventable,’’ he said. “If my sister had known the [hot-line] number existed and dialed it, she would be here. We can’t get Kathy back, but we can help save someone else’s life.’’

Wendy Killeen

The Samaritans’ annual Breakfast for Hope is 8 a.m. Thursday, May 26, at the Westin Copley Plaza, 10 Huntington Ave., Boston. Free and open to the public; donations appreciated. To register, visit samaritanshope.org. Wendy Killeen can be reached at wdkilleen@gmail.com.