I would get him to see a counsellor or someone who can help with his fear/worries as these are more than normal for his age (I am a teacher) Many of the universities run workshops/groups for anxious children, I know Maquarie Uni in sydney does.
When school goes back I will try and find some more info for you.
The other thing I have done in the past for kids very anxious about starting high school is a liason prog with the HS called a Transition to HS. It means the child has more visits to the school and spend more time preparing.