Picky Eater

My three year old grandson is a very picky eater. His menu consists of waffles, raison toast, rice crispies, grilled cheddar cheese with camoflauged grated carrots sandwich, avocado toasted sandwich, all pasta sometimes with tomato sauce, chicken fingers, hamburger, and veal cutlets. The only liquids he will drink is kool-aid, milk and water (mostly milk). He likes crackers and cheddar cheese, fruit bars and very cherry fruit cups. He refuses to try anything else and runs away gagging and getting very upset if we ask him to try anything new.

Last year he would eat a few things more but he got a stomach flu and cut out quite a few things from his menu. He just recently is getting over another stomach flu and now pukes at the sight of things he has been eating. What do we do, his mother is upset and crying and at her wits end, please help.