Yes professional help is always the best ..good luck let us know what they say .
His dad thinks he was around 13-14. His diet is good. He is 5'6 and weighs around 120. We have set up an appointment with an endocrinologist at the end of this month. So maybe we can get peace of mind & hopefully there is no problem. Thanks for your advice.
I think he is still in the range of normal puberty, sometimes there is a heredity factor ,have you asked his Dad when he matured ?What is his weight like , does he eat okay as sometimes undernourishment can be a cause .As you have some concern it may be a good idea for him to see a pediatric endocrinologist,blood tests may be done and a wrist xray for bone age .Treatment if needed is usually a few months of testosterone... good luck