I agree, if the doctor is not on board with trying other methods before surgery then it's time to find another doctor.

Yes blood work is needed especially at his age because both the DHT cream and nolva can effect libido and that's not to much fun at 15 although he might concentrate more on school work than other things. lol

Since he is 15-18% body fat I would consider diet first. Some people just carry fat in different areas and it's hard to get rid of. I think if you got him doing a lot more cardio along with a 500 calorie deficit and get him down to 10% he may loose all of the gyno and it may not come back. I would do this before anything else.