What is happening to zinkoff in chapter 27?

Looking up, he thinks of the snowflakes as stars. He trips, falls, and suddenly screams Claudia's name into the silence. It occurs to him that his mother will be angry that he went out without his hat. Zinkoff thinks of the Waiting Man, and wonders if he ever went to Vietnam in search of his brother. Perhaps he did go, and was there for a long time. He daydreams about a voice from the future saying that everyone searched for Claudia, who was never found. He presses on, not feeling his feet anymore. His mind wanders, and then the snow turns to freezing rain that wakes him up. He did not realize he had lain down and fallen asleep. He jumps up, barks Claudia's name, and calls out to the other searchers. He thinks he calls out and he is not sure. He walks into a garage door and then imagines that the Oh Mailman Lady is inviting him in for cocoa. Through chattering lips, he spells and sings "tintinnabulation." His thoughts touch on many fragments of subjects, including Polly, snickerdoodle cookies, earwax candles, the Yellow team, Jabip and Jaboop, and his fourth-grade teacher, Mr. Yalowitz. Lights flare up, blinding him. He tries to get away, knowing he must continue his search for Claudia, but cannot move, and a voice says, "Hold on, son, I gotcha."