Replicas are the rage these days.
Perhaps he bought a deactivated one, a replica flare/airsoft, or otherwise.
Airsofts can be VERY realistic. I used to own an MP5 full steel airsoft, which gave me some grief when I went to an indoor range to get the cocking tube laser sighted in (it was my long range airsoft, I have a pistol for closer ranges during my games). When I pulled it out, and they saw the safe/singe/3rd/auto markings on the trigger group, they had a tizzy until they realized it was an airsoft. The range there had real MP5s for rental, and they were astouded at how accurate it was from looks, feel AND weight/balance. Given mine was over $700....but an airsoft can look very real and cost very serious cash when you get to the serious sporting grade devices. Mine even had the 9mm markings on the reciever, as well as production marks and serials from a maker licensed to make MP5 or similar firearms (licensed by them).
As for flare launchers...I've seen ones that looked like all kinds of fun devices.
Rule 1, never assume. Rule 2, if you're finding yourself assuming, be sure to remove all doubt with evidence.