The husband of a teacher killed in the massacre has died of a heart attack.

Joe Garcia, the husband of Irma Garcia, one of the two teachers killed in the massacre at Robb Elementary School in Uvalde, Texas, died on Thursday of a heart attack, said his nephew, John Martinez.

Mr. Garcia, 50, had visited his wife’s memorial on Thursday morning to drop off flowers. When he got back home, he “pretty much just fell over,” Mr. Martinez said in an interview Thursday.

The couple had been married for 24 years and had four children, with the oldest 23 and the others teenagers.

Mr. Garcia had been stricken with grief after he lost his wife, Mr. Martinez said. “I’m really in shock right now,” he added.

Ms. Garcia, a teacher for more than two decades, was known as a steadfast optimist in her family. She would crack jokes at gatherings and sing her favorite classic rock tunes during parties, Mr. Martinez said.

“She’s always been optimistic about everything and just so loving with the people in her life,” said Mr. Martinez, 21, a student at Texas State University.

When the authorities went inside the classroom moments after the shooting, Mr. Martinez said, they had “found her body there, embracing children in her arms pretty much until her last breath.”