Actually, that is one of the things I do as a personal trainer in developing the goals of my clients. Which often times is how to gain muscle mass. I do need the height as well, other than the weight...but 195 lbs is considered to be pretty large especially for a 16 year old. (Considering I was recruited as a D1 and D2 athlete for football, but graduated around that weight...I lifted for the beach my Senior year!)
16 year olds that lead active lifestyles are hard to build mass on simply do the rate of their metabolism, and the efficiency of their system when it comes to processing nnutrients, proteins, carbohydrates etc., the only true regimen to follow is an increase in proteins to help build and restore muscle as it is being built ( keep in mind everytime you lift weights you are tearing the muscle, and the protein helps regenerate it) as well as he would definitely have to increase his carbohydrates to help gain the mass you may be looking for.
Those are just the first steps to look at, and if he doesn't like Protein shakes he can get protein from other sources such as Tuna, Chicken breasts, Red Meat, and other forgot abouts such as kidney beans, lima beans, etc.)
ALso his weight training regimen needs to be montiored to accomplish his goals, I understand the BFS program that typical HS's run, which is ok when developing athletes, but mass is gained as well as strengthe with Less reps and more weights. His muscular endurance will come from his other activities, but thisphilosophy is designed to add muscle thus increasing lean muscle mass and weight. (I also would have each muscle group worked to failure by utilizing a drop set method at least once a month.) Very effecitve at stimulating the muscles, and shocking them back into training and getting the body to pass plateaus which accompnay most weight trainers.
I hope this info helps, and if you have any more questions feel free to ask. If I am around and have time I will be sure to answer.