New York-Presbyterian Hospital issued a death certificate for a Brooklyn man whose heart was still beating, and his family is fighting to get the document withdrawn in what experts call an “unprecedented” legal battle.

Yechezkel Nakar, 68, had a vascular condition and had previously suffered a stroke. He wasn’t feeling well in April and went to the emergency room at New York-Presbyterian. He was admitted and took a turn for the worse as the weeks went on, suffering a brain bleed, according to court papers.

Over the objections of his devout Orthodox Jewish family, doctors declared Nakar brain-dead and on May 31 issued a death certificate for him, wife Sarah charges in a Brooklyn Supreme Court filing.

But instead of sending Nakar to a funeral home, they sent him by ambulance to Maimonides Medical Center, where the “dead” man is still on a respirator and being treated weeks later, his family said.

“The man is still living, and the family is distraught at the whole situation,” their lawyer, Morton Avigdor, said.

They want a judge to withdraw Nakar’s death certificate so they can seek insurance reimbursement for his current treatment. Insurance companies won’t pay to treat a dead man.

“To the best of my knowledge, it’s the first time it’s ever happened,” lawyer Mark J. Kurzmann said of the effort to have a death certificate rescinded. Kurzmann, who initially consulted on the case, said, “Something went wrong here, and it’s very, very unfortunate.”

Historically, as well as under Jewish law, a person was considered dead when their heart and lungs stopped functioning. But medical advances have raised the question of whether a brain-dead patient with a still-beating heart is legally and medically “dead,” said Cleveland-based health-care lawyer Harry Brown, who consulted on Nakar’s case.

“The definition of death is not just a physiological one, it has cultural and religious implications as well,” said Brown, an adjunct professor at Case Western University. “In 40 years of being a health-care lawyer, I’ve never heard of . . . a situation with a death certificate issued and the patient is still alive.”

Hospitals can electronically enter death certificates into the city system and typically a funeral-home director would complete the personal information on the form before the city Health Department reviews it, an agency spokesman said.

Rabbi J. David Bleich, a professor of Jewish law at Cardozo Law School who reviewed Nakar’s case, said a patient who is brain-dead but whose heart is still beating can typically die within three to 12 days, even while connected to a respirator. Nakar is still alive, the rabbi noted, adding, “I assure you, there is room for error in everything, including neurological criteria.”

George Mason University law professor Michael Krauss, who is not connected to the case, said New York-Presbyterian’s own actions undermine their decision to issue the death certificate.

“It’s extremely unusual that they declared the man dead if the family objected to the cessation of life support,” he said.

New York-Presbyterian declined to comment.