Hi, I can help you with your question today.
I'm so sorry you have been going through this with Woods. Do you have a copy of his lab testing? I would be happy to take a look if you have it. Aside from that, the most common conditions which might cause his clinical signs are kidney disease or pancreatitis.
The blood test for pancreatitis is a specific one that is not included on most general screening panels. Do you know if your vet has ordered this particular test (an fPL - feline pancreatic lipase)?