Welcome xsantos! You might like to start your own thread on this, but my initial questions would be why your son doesn't write in school, according to him. What does he say when you ask him? Seems there are many possible explanations based on what you said, that would need different responses. My DS was a reluctant writer for years but with help and encouragement improved.
(DS = dear son; as this is a public forum we mostly avoid using real names. My DS is not called Colin! I've avoided using your DS's name here in case you decide to edit it out of your post.)
