I agree with Deus. Just be there for him, learn WITH him, oh, and carry his insulin and blood glucose meter around in your bag for him when you go out together

(i dont make Laura carry mine at all!!!

)
Seriously though, if he does have diabetes, it's not the end of the world. it'll open your eyes to all the "****" you shouldn't be eating and you'll both live healthier lives (because you're not going to eat **** infront of him when he can't... are you?)
Good Luck!!