A big-bellied man who wears beachy clothes in all seasons, Mr. Brand refers to himself as “the flower guy.” He has worked in the fabric flower trade since his teens and remains, he said, “obsessed about it.” Sometimes he lies in bed at night and thinks up new shapes to make with the firm’s hundreds of flower molds.

He called the students’ attention to a printed photo of an old man taped to a nearby wall: his late father , Harold Brand, a Holocaust survivor born in Poland.

“He had two brothers, a sister, a mom and dad. They all got perished ,” Mr. Brand said, explaining how Harold emigrated to America after the war and worked at Schmalberg, which was started by his uncles. Harold eventually bought the business and ran it until the 1980s, when Warren and his sister, Debra, took over.

“Years ago, when I was a kid,” Mr. Brand told the students, “we sold thousands of flowers to children’s companies for little girls’ dresses. And then all that big industry of children’s garments stopped being made in America.”

The family used to have a street-level store on 35th Street. “Next door to us was a button man. The other side was a thread man. And a zipper guy,” he said. “Now you walk the streets and everything’s coming in a box, off a boat, made in La-La Land.”

Warren’s son, Adam Brand, who is 35 and began working with his father nine years ago, watched from the sidelines. Among his many duties, the younger Mr. Brand handles marketing and social media, essential for finding new, younger clients to replace the lost accounts.