Has your friend seen his doctor to discuss diet and his weight? He will need to consider physical activity because that is part of losing weight.
A lot of people have had success with weight loss when they use the food log here on fitday. If your friend measures what he eats and then enters it in a daily food log, he will see how many calories he is taking in every day. His doctor can also use that information when they discuss weight loss programs and diets.
Good luck to your friend. It's good he has a concerned friend like you!