Your son has delayed milestones. There are many causes for it and common ones are Thyroid
), Cereberal palsy
and Down Syndrome.In order to ascertain the cause you must provide the details of his birth history and any problems associated with his birth like mode of delivery, delayed gasping and crying,jaundice
, seizures or any post natal infection. If you can send a picture of his face and hands at my email address, I may be able to help you further.