Check with local pet food store, they will have some special diets for small dogs, as this mix sounds like he would not be too big. Regular dog food is okay, but if you want to feed him something that will meet his special requirements, best to ask the experts.
ANYTHING! I have a ten year old (her name's Casey) and she will literally eat anything. Any dog food, any people food (which is a problem).
My dog will turn 1year old in 1-16-2010