Hang in there, it will be okay
. Thankfully, diabetes is a disease that is quite easily managed with insulin. I'm not sure whether they'll put your kiddo on a lower carb/higher protein diet but if they do...it's okay. Your other dogs can also have higher protein, as long as they don't have some underlying disease that contraindicates it. Lots of us here have our dogs on higher protein diets since canines are designed to have a lot of protein in their diets.
Please keep us posted!