If you have time, I would also suggest that you watch 星期二檔案 (from 2008-09-16). It was a program on Asperger's Syndrome. See if your child is in any way resembles to the girl in the program.
It is very difficult to say whether your child is okay or not just based on your description. If you have any doubt about the condition of your child, you should bring him to an assessment as soon as possible.