Can a high protein diet give a dog Canine Diabetes?

No,a high protein diet would not cause diabetes,but it may affect the kidneys of an older dog.The symptoms sound like the dog may be developing renal failure,but it could be diabetes or Cushing's disease,or even something as simple as a urinary tract infection.. The food you are feeding is not a high protein food. 21% protein is a moderate amount of protein which most any dog can handle. You just need to have the dog checked out asap. Ask your parents to at least take a urine sample in to the vet until you get home.