<<Disclaimer: Verify this information before applying it to your situation.>>
 
I have found the "Gluten Free Gourmet" as the best source of recipes.
 
I have made the carrot cake into cupcakes or muffins.  It is really good.
 There is  also an excellent chocolate cake recipe - Black Forrest Cake -
that always gets rave reviews.
 
Does the child have access to a microwave or can the school heat things up?
 I use a bag with ice packs in it to take leftovers.  Dannon yogurt is good.
 You could send pizza (again from the GF Gourmet).  The thick yeast crust is
good and the sauce on the next page is also good,  I omit the sugar.  There
are GF soups available as well as homemade chicken noodle with GF pasta.
 Good luck.