This patient support community is for questions related to juvenile diabetes including
Celiac disease,
depression, diabetic complications, hyperglycemia /
diabetic keto-acidosis,
hypoglycemia, islet cell transplantation,
nutrition, parenting a diabetic child, pregnancy, pump therapy, school issues, and teens with
diabetes.
So if he is diabetic, he probably should first test his glucose levels when you smell this smell -- if they are normal, then there may be other reasons such as were mentioned in the answer above this comment for the odor.