1. take a multivitamin with zinc
2. his daily diet looks like this: milkshake (ice cream, whole milk, cream, sometimes chocolate syrup or jam), 2 or 3 scrambled eggs (with butter) OR a donut OR yogurt. He's not a morning person, so that's a lot for him. Lunch at school (he's a senior)is leftovers, or an UDI's bagel with peanut butter, hershey bars, yogurt, homemade choc chip cookies (tell your mom to search for "Chewy Gluten Free" from Food network. Best. cookies. evah.), cheese squares, graham crackers (sometimes we cover them in chocolate). Dinner is a protein, veggies, rice or potatos smothered in olive oil or butter. He always eats something(s) between dinner and bedtime. I cook all his food with butter.
Favorite foods: cheese, peanut butter, olive oil, whole milk, avocados (he eats 'em plain), hershey bars, M&Ms, blueberry pancakes (he eats them cold. King Arthur gluten-free Mix is what we use), Tostitos, tater tots, hot dogs, klondike bars, pudding...
His nutritionist said not to worry too much about WHAT the calories come from at this point, just try to get at least 500-600 at every meal and 500 at every mini-meal. It's a lot of work to eat that much! You might also try google-ing high performance athletes diets -- they have a similar problem, although for different reasons. As a relatively young man, you just burn so much calories its hard to keep up! Think of it as a contest, a goal --- some of the food isn't your favorite, but it will get you healthier. Good luck!