Hello and thanks for your question!
Your question raises more questions that I have to ask first before I make an informed answer for you and your friend:
Is he losing weight? Does he think he's fat? is his food portions very small? Is he NOT at a healthy weight?
If the answers are no to the above, I do not beleive he has an eating disorder. He is just eating unhealthfuly. he needs to add more nutritious foods to his diet. If you notice that he is losing weight to a point where he is extremily thin, then I would say he has an eating disorder. Possibly EDNOS even Anorexia Nervosa.