“We want people to forget about their problems. When he comes and performs, he makes them laugh, and we like that,” said Zabiullah Sharifi, the hotel owner. “But he curses a lot and sometimes bothers people.”

It has become a constant concern for his mother, who dotes on Zabi, her eldest child. She worries when he is out, wondering whether he has been picked up or beaten by people who dislike his impersonations. He is prone to wandering the city, stopping to see friends who pay him a dollar or two for his impersonations.

She calls his friends sometimes, asking them whether he is bothering them, though mostly just to see if he is all right.

“Sometimes when he comes home late, I send his brother to look for him or I go out myself,” said his mother, a schoolteacher. “We are extremely worried about him, where he goes, whom he is with, because we are worried somebody might hurt him.”

Seated together in their family home, in a barren apartment block in midconstruction, they picked at each other playfully. She chastised Zabi for his chain-smoking. He shrugged, then left the room to have another cigarette.

The two have tried to keep Zabi’s impersonations of Mr. Karzai a relative secret in their neighborhood. He seldom performs nearby, and then only cautiously, and she has not told her colleagues that her son is a famous impersonator.

Early in Zabi’s run as a performer, she recalled, her fellow teachers listened to what they thought was a recording of President Karzai. Only it was Zabi, promising the teachers of Afghanistan higher salaries and free plots of land.