"The Son From America" is postmodern in being a modern fabula or folktale rather than a realistic or modernist work of literature. It shares similarities with stories such as "The Handsomest Drowned Man in the World" by Gabriel García Márquez.
Set in an indeterminate period in the late nineteenth or early twentieth century, "The Son From America" is a modern fable. The story veers away from realism to embrace the folkloric in the stark simplicity and purity of the lives of the two main characters, Berl and Berlcha. The Jewish couple lives in a village in Poland, having been driven from Russia. In a realistic story, they would suffer from their poverty, as would their fellow townspeople, but in this self-conscious literary piece, they want for nothing. All their needs are met by living in a one-room cottage without even kerosene lamps, with their goats and their chickens. They are never hungry or in any need. They have never needed to use the money their son has been sending for years from America.
When their son comes to visit, they mistake him for a nobleman and call him that because he is so tall and well-dressed. He comes wanting to help them, their synagogue, and their village, but he discovers that in their simplicity, they want for nothing. The son learns a moral lesson about contentment, realizing that giving the village more would only ruin its perfect equilibrium.
A modernist story would typically exhibit much more interiority by exploring the psyches of the characters, even if done in a stark way. In this story, the characters are flat and simple: what you see on the outside defines who they are. And because the story is placed more or less outside of the anxieties of history as we understand it (though there are mentions of the tsar and allusions to anti-Semitism), it does not comment on modern angst directly, as a modernist story would.
The story is postmodern in being a modern fable, playing on an oral tradition of folktales, but set roughly in modern times and self-consciously literary.