I have been diabetic since I was 8 and I am 29 now. Juice is the fastest thing to raise blood sugar levels. Any sugar is good. You can buy glucose tablets that can be carried easy but juice is best. If his levels drop he needs something fast acting juice, candy, glucose tabs but he also needs solid food to stay with him in his system because sugars from candy and everything are gone again in a hour or two. Man sugars going low sucks and I feel for your boyfriend.