"Dallas was more than a founder. He was a friend who was dearly loved by everyone he touched," Jason Gerner, chief operating officer of Liberation Way, said in comments published online by PRNewswire.
Gerner said he was "shocked, in denial," when he heard about Mr. Fetterman's death.
"Dallas forged the path for so many people to get help from their addiction," Gerner said. "He is responsible for not only saving many lives but for also changing them, and making them become happy, healthy, and productive members of society."
Gerner said he did not know what drug caused the overdose of his friend and partner in the organization. He said he did not know that Mr. Fetterman was relapsing.
"There is an unfortunate stigma and also a high standard attached to professionals working in the field of addition, and in this case, too often there is a psychological price for entrepreneurship," Gerner said.
Gerner said Mr. Fetterman didn't focus on "war stories," but on helping people.
Liberation Way has facilities in Yardley, Bala Cynwyd, Fort Washington, and Collingswood, N.J. Gerner said about 800 people were helped through the centers.
Mr. Fetterman hailed from the Wilkes-Barre area. Michele Davis, a high school friend, said he was "vivacious, a ball of fire, and funny as hell" in his younger years.
Big-hearted, Mr. Fetterman helped Davis do a fund-raiser for a local family. In later years, she said, she reached out to him for advice about treatment for someone she knew, and he was generous with his time and information.
"He never stopped trying to help," she said.
Davis said quite a few people in her area have drug problems, particularly with opioids. People knew Mr. Fetterman was involved in treatment.
"I think Dallas was an inspiration to a lot of people, and a success story," Davis said. "It's disheartening, because he was a lot of people's hero. I saw a lot of people on Facebook blown away by it."
He is survived by his wife, Cindy, and a daughter. Mr. Fetterman's survivors plan to carry on his work.