14 year old with poor concentration and anxiety-sweaty palms

Hi All, My 14 year old son is an excellent student who has difficulty paying attention and unable to concentrate in school and at home. When he was 6 months old, he fell off the bed and hit his head on the hard tile floor.(no blood) He takes 4 times longer to finish his homework than his classmates. He has trouble with common sense is a slow thinker and writing his thoughts is difficult. He gets sweaty palms and feet when anxious and nervous. He seems calm but inside he's anxious esp. around his peers and before a performance. He plays a few musical instruments well but long after he stops playing he can often hear music in his mind. Playing sports is very difficult for him. His eyes are sometimes glossy and hazy and sometimes has slurred speech and doesn't make sense. Does not use illegal drugs. He is well behaved and well liked by the adults that know him but is intimidated by his peers and separates himself from them. Sometimes they tease him.He doesn't take any medicine and is allergic to penicillain and shrimp.

He's afraid to go into a dark room but can sleep with the lights off. He snores loudly and has had nightmares. At four he had a hernia operation and sufered with the croup for a few years. He has won several academic achievement awards despite the obstacles.
We welcome all suggestions and Thank You.

Good health to you!