ah good luck to him, i know you are his trainer and all but id be giving him some hard constant drills on the bag and . fast work out and heavy punching etc. and exercises until he gets the stamina to run a mile or 2 and go on from there how is his weight now
My dad has a cousin roughly that size. Mexican, of course... but he's a grown man. You don't see too many Mexicans walking around that size... expecially not 14 year olds!