Neither of the other dogs are showing any signs of problems? If the other dogs are showing symptoms, but milder, could be food or parasites or something, and Toby's system couldn't handle it as well. So watch for problems on the others.
Also, find a 24-hour ER in your area, that you can use for emergencies. Ours only gives enough meds, etc. to make it a couple of days until we can follow up with our regular vet. And that way you have an extra set of eyes looking at the problem.
My parents cat lost weight slowly like that over the course of 8 or 10 months. They finally diagnosed her with diabetes. By the time they started with insulin, the cat was done. They had to put her down. I haven't really heard of shepherds with diabetes, though.
Could have been a blockage, could have been many different things.
So sad about your dog though. I am sorry this happened.
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