PITTSBURGH—When Michael Kerr asked around Pittsburgh’s gay community for a physician knowledgeable about HIV, he was told one name: Dr. Jerry Rabinowitz.

Kerr was a graduate student at the University of Pittsburgh in 1989 when he was overcome with flu-like symptoms. Studying medicine, he knew the symptoms meant he was HIV positive. The disease was stigmatized and misunderstood, but Rabinowitz had a reputation for his knowledge of HIV and AIDS treatments and conscientiousness to gay men.

“I never knew what it was like to go to a doctor who wouldn’t shun you or treat you with stigma around the issue of sex [until Rabinowitz],” Kerr, 54, told The Daily Beast. “It was the first time I could open up and have conversations about myself.”

Rabinowitz was a beloved physician who was murdered at the Tree of Life synagogue on Saturday alongside 10 other people. His reputation was earned on the front lines of the HIV/AIDS epidemic, in its earliest days.

Gay men of Pittsburgh sought out Rabinowitz even when he was a young medical resident at Shadyside Hospital in the late 1970s. Martin Seltman, who was a resident with Rabinowitz, said young men came in with pneumocystis pneumonia and other conditions for which HIV/AIDS was the underlining cause, before the Centers for Disease Control gave the disease a name in 1981.

“We lead a very isolated existence,” Seltman said. “But people were coming in asking for us. … A lot of gay men were getting referrals.”

Seltman remembers Rabinowitz, who started residency before him, as a mentor.

“He was someone I looked up to, who I would ask about things when I didn’t understand them.”

Even after Rabinowitz set up his own family practice near Shadyside Hospital, those referrals kept coming, including the one passed to Kerr in 1989.

Kerr says he made a deal with Rabinowitz: He only wanted to know when his T cell count had dropped to such a point he would need to start taking medication, like azidothymidine (AZT), which had horrific side effects. Kerr did not want to start taking it until his T cell levels dropped to a point where it was absolutely necessary. In 1995, Rabinowitz told him he needed to be on medication and helped Kerr enroll in a study for two new medications. By early 1996 Kerr says his HIV was undetectable.

“I got care as good as I would have had I been in New York or San Francisco,” says Kerr.

It wasn’t just the medical care that kept Kerr alive he says; it was seeing a doctor who could consistently engage him and make him feel that medical treatment could, in his lifetime, offer an answer and helped him stick with it.

“He never said, ‘It will be OK’ or ‘Don’t worry.’ He had lost patients. But he showed me I was being cared for and he appreciated that I was scared.”

Kerr last communicated with Rabinowitz in 2005. On Saturday, a former coworker texted Kerr when the news came of the shooting: “Do you think among those lost is our Jerry?”

On Sunday, Kerr found out that he was.

“I’m sick to my stomach,” says Kerr. “I am never going to be able to tell him I made it.”