Cat Liver Disease?

Question
I have a neutered male cat that is 13 + years old. My vet thinks he is 16. The cat is very underweight at about 6 pounds. He has a healthy appetite and begs for more "wet food," but will not gain weight. He urinates frequently in his box. He also vomits bile and a foamy substance and chunks of food on occassion. Sometimes he makes the vomiting sound, but nothing comes up.

I was wondering what this could be and what options I have for him. I cannot afford to really do anything drastic, but what can I do meantime to make his life more comfortable?

Thanks!

Answer
Blood tests should be run to check kidney and liver function as well as test for diabetes and hyperthyroidism as all of them can cause weight loss, vomiting and increased urination.  Depending on the results, appropriate treatment can be started.

I would recommend trying a bland diet such as meat baby food, boiled chicken and plain yogurt to see if that helps reduce the vomiting.  He should eat 4-5 small meals a day.