“I believe she passed away,” said Ms. Solis, who led the family’s increasingly frantic search for Ms. Correa from her bedroom in the Bronx, where she was isolated with coronavirus-like symptoms. “But where?”

She added: “If she went to Jamaica Hospital, don’t they have cameras who show who goes in and out? Isn’t there paperwork to show when she arrived?”

Hoping for help, Ms. Solis reached out last week to The New York Times, which contacted Jamaica Hospital on her behalf on Monday morning.

The hospital said in a statement to The Times on Monday that it could not find a patient with Ms. Correa’s name or birth date: May 12, 1946. The hospital declined to comment further, citing medical information privacy laws.

The suffering at Ms. Correa’s compact, three-story house in Woodhaven started in late March. Amparo Holguin, Ms. Solis’s mother who also lived there, had felt sick for about a week with gastrointestinal symptoms. She went to an urgent care facility, where, despite her elevated heart rate, blood pressure and temperature, a doctor gave her a diagnosis of simple gastroenteritis and prescribed antibiotics, according to paperwork from that visit. There was no mention of coronavirus.

By the following afternoon, March 24, Ms. Holguin, also a diabetic, could not recognize family members. She was talking about “God and gibberish,” Ms. Solis said. She was breathing heavily, so they made a pot of steam to ease her airways. Then her blood sugar spiked and she collapsed in the living room.

Ms. Solis, 49, was instructed by a 911 dispatcher to give her mother CPR as they waited for an ambulance. Ms. Holguin could not be revived. Her body lay in the living room until 11 p.m. that night, Ms. Solis said, when they were lucky enough to find a funeral home to take her away.