He is severely underestimating how much co2 is produced in the first 72 hours while the yeast is most active. If he doesnt buy or make an airlock, hes going to have to burp that bottle every hour.
Hell, a ballon, with the opening stretched over the mouth of the bottle, held secure with a rubber band, and a tiny pin prick on the baloon body is the cheapest and easiest airlock he could do. The co2 pressure is higher than the outside air and it will press out of the hole without letting air back in.
He could also drill a hole into the lid of the bottle, glue or epoxy a rubber hose into the hole, and then run the hose down into a cup of water beside the bottle with the wine.
Either of those options he could probably do with shit he has laying around his apartment.