I am a school nurse and would appreciate help and guidance on Halāl diet for a 12 year old who boards with us on a weekly basis.

You can give the boy whatever you want, except for the food obtained from:

1. Pigs

2. Dead animals

3. Animals which are not slaughtered the Islamic way1 

4. Animals whose abhorrence is found in human nature

1. This means that they must be slaughtered through their jugular veins and the name of Allah should be invoked while slaughtering the animal.