Eddie, this is something we are trying to work out as well. My wife was in hospital for a few days between Boxing Day and New Year (given she is cricket mad this wasn't easy!!!) and it turns out she has Type 1 Diabetes too.
At the moment she is paranoid about her sugar levels, and is very nervous about being away from medical treatment, so won't be doing any big walks soon. I did manage to take her on an easy day walk last week -- her first since the diagnosis -- and her BSL's were perfect. (
http://bushwalk.com/forum/viewtopic.php?f=47&t=8692) Hopefully that encourages her to walk a little further.
In the long term walking will actually be a really good way for her to keep her diabetes under control, but it will take time to build up confidence in how her body deals with exercise.
I have been told of diabetics who are very active walkers. In fact, a friend said told me the benefit of a diabetic trip leader is that you can guarantee you will have meals on time and stop for snack breaks, so they are often quite popular!
Hope all goes well with your young one. I think the reality these days is that Diabetes doesn't really stop you doing much, but it will take some time for him to get to understand how his body now works and to build up his confidence in how he manages it.
Tim