Does he have to eat traditional "breakfast" foods? If not, the resort gift shops are full of things you can have. Bread, peanut butter, baloney, cheese, plus sweet stuff like Entenmanns. You can buy pre-cooked bacon that doesn't have to be refrigerated and doesn't take up a lot of room in your suitcase, or those pre-made tuna or chicken salad packs.
We like bagels and cream cheese or peanut butter for breakfast or cereal.