Grace Fusco — mother of 11, grandmother of 27 — would sit in the same pew at church each Sunday, surrounded by nearly a dozen members of her sprawling Italian-American family. Sunday dinners drew an even larger crowd to her home in central New Jersey.

Now, her close-knit clan is united anew by unspeakable grief: Mrs. Fusco, 73, died on Wednesday night after contracting the coronavirus — hours after her son died from the virus and five days after her daughter’s death, a relative said.

On Thursday, another child who had contracted the virus, Vincent Fusco, died, the relative, Roseann Paradiso Fodera, said.

Three other children remain hospitalized, two of them in critical condition, said Ms. Paradiso Fodera, the family’s lawyer who is Mrs. Fusco’s cousin and is serving as a spokeswoman.