well, depends on his body type (i.e. weight, whether he's athletic or fat) and how severe it is. My suggestion is that he should sweat it out a couple of years since he is only 16 and his body will still be going through some major changes - he should do some lifting and cardio and that may do it if he has mild gyno.
If there is a lot of fatty/glandular tissue in his breast area still after the couple of years, then he'd have to see a plastic surgeon to get rid of it and have it sucked out and contoured accordingly. A good resource is gynocomastia.org, it's a forum just like this one. However, like i say, he is young - so the surgery isn't a good idea yet. Wait till his body settles a bit so that his gyno doesn't recur in his 20s.
Hope this helps.
If there is a lot of fatty/glandular tissue in his breast area still after the couple of years, then he'd have to see a plastic surgeon to get rid of it and have it sucked out and contoured accordingly. A good resource is gynocomastia.org, it's a forum just like this one. However, like i say, he is young - so the surgery isn't a good idea yet. Wait till his body settles a bit so that his gyno doesn't recur in his 20s.
Hope this helps.