Speaking as someone who was diagnosed at 5 years of age, I would stress to make sure that your child is not afraid to eat what they want. Sugar is not bad for them any more than regular carbohydrate - you just need to accommodate it correctly with insulin. Both at the end of the day, raise blood sugar levels - only difference is speed. 10g of fast carbs gets the same result of 10g of regular carbs if no insulin is taken.
It was not available to me when I was younger (I have done the adult equivalent called DAFNE though) but take a look at doing KICk-OFF (which stands for Kids In Control OF Food)
http://www.kick-off.org.uk/index.php
It is all about helping your youngster understand things like carbohydrate counting, insulin doses, etc, which is probably what you're very much in need of right now. I would be very surprised if they don't cover parental education as well as part of the course.
The adult course called DAFNE (Dose Adjustment For Normal Eating) was about a week long (because it takes days of practice to come to terms with the new way of thinking and understand what is happening...). I am not sure if this is the same for KICk-OFF.
Either way, sorry to hear that your little boy has been diagnosed but I'm sure he'll be okay because you clearly think the world of him. My thoughts are with him and I wish you the best with his future health!