Originally Posted by Tar Heel Tennis
Why don't you record his serve, then send him the video? Simply explain to him that he foot faults consistently, and provide him with evidence.
It sounds like he is an honest player, and may not know that he is gaining an advantage with his service technique.
Good luck, and please let us know the results.
Sorry, this seems a little xtreme! Recording him while he's serving! Would you let him know he is being recorded or just catch him off guard? Evidence, are you taking him to court (pardon the pun). That would go over like a lead ballon..pardon the cliche.