A phone that does not charge is more of a paperweight and less of a phone. Let's see what is going on with your son's phone, is he using the original charger that came with the phone? Does his phone show any error messages when he connects it to the charger? Does the device have any physical or water damage? Please share details so we can better assist you.
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If he has another syncing cable he can test out to make sure it isn't defective have him do that. Also try using the current cable with a computer to see if it works. If so then the issue would be the wall charger. If it doesn't work using a different syncing cable with the wall charger or the computer then it would be the device. Assuming it hasn't had any damage that would void the warranty (water/liquid getting into the port for example) then it would be replaced/repaired under the manufacturer warranty or AppleCare+ (if he has it) will cover it even if there is damage. I always recommend going to Apple if you have a store in your area as you won't get any surprises like some have had with Verizon (such as being charged later for the exchanged device because they say the original one was damaged), but he can always opt to have Verizon exchange it if that would be easier.
Ever since this last update mine won't charge and if it does it takes hours and the battery drains with nothing on. Im using the same chargers I was a week ago when it charged in no time and before this last update.
Charge your phone up, back it up to iTunes, and do a restore of the device via iTunes. This will re-apply the software update from scratch, update any firmware (including potential battery-related firmware), and restore your data.
Make sure that you use an Apple branded cable and plug. Sometimes wall plugs and cables are at fault, specially non-Apple ones. Also, make sure that the charging cable is not worn with cuts (I was trying to find the word. English is not native tongue. I think it's "frayed") at the end, specially just above the plastic wrapping just above the 8-point connector.