David Zysk Jr. was a key member of the Portland recovery community, spending much of his time working with addicts and the homeless. But 33-year-old who had devoted himself to helping others died alone in a South Portland hotel room last weekend, a victim of his own struggle with heroin addiction.

“He saved so many others, but could not save himself, ultimately,” said his mother, Mary Jeralds. “He died from a one-time relapse, but he would hate that word, relapse.”

His family confirmed that Zysk, whose body was discovered Monday, died from a heroin or fentanyl overdose.

A Wells resident, he worked as a case manager at the Preble Street Resource Center. He had been sober for four years and was a senior at the University of Southern Maine, where he maintained a 3.98 grade point average and expected to earn his bachelor’s degree in social work in May. He was considering going to graduate school at USM, Jeralds said.

She described her son as a fierce advocate for substance abuse treatment, a champion for those in recovery and an excellent communicator in one-on-one counseling.

Alison Lovejoy, team coordinator at Preble Street, said Zysk held himself and others to high standards and made the work force more effective.

“He was just as comfortable sitting on the curb talking to someone, sitting in the offices or in a courtroom if need be,” Lovejoy said. “And he was just as comfortable advocating for public policy solutions.”

Zysk also served on the Portland mayor’s Substance Abuse Committee, the city’s Overdose Prevention Task Force, Young People in Recovery and the Maine Harm Reduction Alliance, an Ellsworth nonprofit advocacy group.

“He just wanted people to be treated with dignity and respect,” Jeralds said. “He had a special connection with people. It was his passion and joy.”

Zysk’s friend Andrew Kiezulas, a fellow USM student also in recovery, said Zysk “felt compelled to stand up for others.” While Zysk appeared to be on the right path, he said, his death was a reminder that recovery is always challenging.

“We’re all in very vulnerable positions as people in recovery,” Kiezulas said. “Substance abuse disorder can strike down anyone, even someone in good circumstances.”

Jeralds said her son always seemed to suffer from depression near the end of the year, and that his father, David Zysk Sr., died about three years ago in the late fall.

In addition to his mother, Zysk is survived by his 18-month-old son, Jaxson; his girlfriend, Aubreyanna Boston; his sister Carly and three nephews.

Funeral arrangements are being handled by Autumn Green Funeral Home in Alfred.