Beloved NYC hospital worker took in her older brother — before he allegedly strangled her to death: ‘Just senseless’

A beloved Brooklyn hospital worker who was found slain in her apartment had taken in her older brother to care for him — only for him to allegedly strangle her, according to friends and police.

Pals and co-workers who spoke to The Post this week saw it as the ultimate betrayal of caring Mary Fagan, 64, whose body was discovered by EMTs July 26 in her Crown Heights home.

“She took in her brother and that’s the same hands that killed her,” one nurse who worked with Fagan at New York Presbyterian Hospital said.

“I was really sad before. But at this point, it makes me really angry, because she talked about her brother all the time,” the woman, who requested anonymity, said.

“She took care of that guy. Her life was to take care of her family,” the nurse said. “The lady was so hard working and she just died, just like that. Just senseless.”

Thomas Fagan, 68, allegedly admitted to cops that he strangled his younger sister following his arrest on Saturday — although the circumstances and a motive have not yet been revealed, law-enforcement sources said.

It was unclear when Thomas moved in, but neighbors said he was only recently a presence.

He was arraigned on a murder charge Sunday and ordered held without bail.

Mary Fagan worked at the hospital for about 30 years as an environmental services worker in charge of cleaning and disinfecting the facilities, friends and co-workers said.

She was known as a generous and giving person — both at home and on the job.

“She was very quiet, she was helpful,” one neighbor, a 91-year-old retired nurse, said Tuesday.

“She always offered to help me because I was quite a big older than her,” the woman said. “She was like, ‘Can I help you?’ She went me a bag of cookies on day.

“I’m still in shock in a way, I mean, she lived right down there from here, a hop, skip and jump,” the neighbor said.

Friends described her brother as “very nice, polite,” — and said they never heard the siblings arguing.

“He never said anything,” one neighbor said. “He just would come outside and smoke a cigarette.”