No ketones/DKA (Diabetic KetoAcidosis) experience here either, but if that is what it is then hydration, food, antibiotics and insulin are all really important. I would ask your vet to clarify the diagnosis and the ketone reading (or you can include the test results here...blur out your personal info).
If that is the case and you have problems with any of these (e.g. Won't drink, won't eat, problems shooting insulin, problems giving antibiotics or vomiting), please post in the main health forum asap with "DKA" in the title so that folks who have dealt with it directly can help.
Welcome to you both, you are in the right place.
Sandi.