Helen Ochisor drove the yellow taxi in the morning. Her husband Nicanor took it in the afternoon.

They rarely saw each other during the week. She was asleep when he got home after a long night of driving. They exchanged a quick hello while handing off the taxi.

Immigrants from Romania, the couple had bought their New York City taxi medallion nearly three decades ago. Lately, it had been difficult to find fares. Her husband worked 12-hour shifts, but brought home less money. He was worried about the plunging value of their once-lucrative medallion and frustrated about Uber’s takeover of the industry.

On a cold day in March, Mr. Ochisor hanged himself in his garage in Queens. His family blames the growing hopelessness he felt over his fortunes as a taxi driver.

“It depressed him, it irritated him, it probably angered him — maybe all three,” his son Gabriel Ochisor said in an interview at the family’s home. “It was definitely a factor. Otherwise, we can’t piece together any other factor.”