If he has to be stuck in an airport, the Delhi airport is a good choice. They have sleeping lounges (at least they did when I was their in 2001) where you can sleep, although with zero privacy.
Many airports nowadays seem to be deliberately hostile to sleepy travellers, most commonly by having armrests between all seats so you can't lie down across several, but sometimes even by having staff come around and wake up sleeping travellers on a regular basis. The Guide to Sleeping in Airports exists for a reason, and it rates New Delhi highly: https://www.sleepinginairports.net/guides/new-delhi-airport-...