Thinking of him supersal, hope it's good news by now, our 17yr old is bleeding us dry until he starts earning (fingers crossed at end of August) so I feel your pain!! Well done to him for getting an interview even, there's not much for youngsters out there, sending positive vibes to you! xx
tell him that if they say this at his next interview i.e. more work experience then to offer to come in for a trial period (unpaid but a set time i.e. a week) so that he has the opportunity to show the employer what he can do. It will show the employer that he is serious about the job, how quick he can learn, but also he will get the some experience so if that job doesn't work out then he can talk about dealing with a difficult customer, handling cash, taking orders etc etc at his next interview.