Sounds like he needs to reset the key fob. Tell him to:
1) Get in and close all doors. Turn ignition on and off quickly and remove the key (all within about 5 seconds).
2) Within 30 seconds of turning the ignition off, while holding down the "unlock" button, press the "lock" button three times. Release the "unlock" button. (You may or may not get the confirmation from the door locks.) Holding the key at your head level provides best results as the key sensor
is in the side window pillar.
3) Repeat for each key you want to initialize within 30 seconds after the last one you initialized (if you have more).
4) Right after doing the last key, quickly put the key back in the ignition and turn it on/off again to finalize.