This sounds exactly like what happened to Mac. He stopped eating and was losing weight. The vet ran some tests, found out it was his thyroid, and sent him home with thyroid pills (fairly inexpensive) and some appetite stimulants. He has been on the thyroid pills since last summer and is doing great! He is almost Grandma's age, about 15-years-old, so I think getting older has something to do with thyroid problems in cats. My vet said that as long as he took the pills, he could live for many more years. I sure hope so. I'm glad Grandma is coming home. Ask if they can send some appetite stimulant pills home. They really get them eating!