For another time on Wednesday, President Trump somberly described a personal connection to the coronavirus as he discussed the effects of the pandemic at his daily briefing with his virus task force.

Sometimes he has referred to a friend who has the coronavirus and other times to friends. His aides have repeatedly declined to identify whom the president has been talking about.

But three people familiar with the matter said he was describing Stanley Chera, a New York City real-estate developer who has known the president for many years and had decamped to Deal, N.J., a few weeks ago as the coronavirus spread.

But it was unclear whom else Mr. Trump might have been referring to when he said he has other friends who are also ill.