I know that along with the fact that he refuses to accept it or to take medical help. I was also diagnosed the same some years back and today Alhamdolillah I'm managing without medication and any problems. I wish i could make people understand that it not as simple as they think. It's a season change effect, like those with allergies start getting more ill from mid february to mid april, likewise psy patients also start getting these health issues during this time.
To someone who is on controlled medication or has recovered after a medical treatment the simple precautions for this seasonal effects are to : reduce intake of tea/coffee, must follow a proper sleep pattern, some excercise, lot of citrus fruits and a few other techniques