Hello.......i understand your concern ,since you are medical student you are very much corcerned about his health. If he is not having old age problems like hypertension and diabetes its good. Even he shouldn't do such a heavy duty at this at this age, if it's a financial problem, it's inevitable to work.... Since he is chattered accountant and sits a for long time simple healthy food it good for him, his diet should contain lot of vegetables, avoiding out door foods, oily foods it good. Routine check up, and exercise at least walking is required to burn calories.