I have type 1 diabetes and if these symptoms have been going on for 12 months then I wouldnt think
He has it. It a matter of 3-4 months of my symptoms going from mild to severe the doctors were surprised I wasnt comatosed (sp?). My symptoms were constant thirst and urination severly dehydrated to the point I couldn't speak without having a drink first because my mouth was so dry, rapid weight loss, I'd gone from 73kgs to 59 kgs in ten weeks. Constantly tired I couldn't hang a load of washing without needing to sit down for an hour. If your son is having a big reaction to sugar then it might be sugar related because when your a diabetic the sugar doesn't go into your red blood cells to be burnt off for energy which is why you crave sugar so intently and your body burns off your fat stores for energy which is why rapid weight loss is a symptom. Also because the sugar is t turning into energy it builds up and up in your blood stream which is why diabetics feel like crap when we're running high. And it's also why we drink and urinate alot pre diagnosis because your body can't pee sugar crystals and needs to dilute them.
Hope I've helped in some way