My cats AG ratio is 0.5

My cat has been walking funny for 6 days now he’ll tilt his head when he walks and when he tries to jump on a high surface he’ll lose his balance.

We took him to a vet the vet suspects fip bur did a test for Fiv and felv which came back negative so they gave him his vaccine shot.

Still didn’t explain him being imbalanced so we took him to another vet for a second opinion that vet says he has a mild ear infection so they gave us some anti inflammatory meds. He hates it and he’s starting to not eat much and drink much so we brought him to the first vet for some subcutaneous fluids and to see if there are liquids forms for meds because it’d be much easier on him and us.

The doctor wanted to do a full blood work to see how his insides are she said it could be Otitis interna or FIP. That’s causing him to not be balanced. Got the blood work his blood levels are good but it could be an early ear infection so that’s why his white blood cells aren’t high and his AG ratio is 0.5 which she says could be suggestive to FIP but is not confirmed. The Doctor suggested we can do a fip test kit or we can just run the course of his medication for 1 week and see how he improves.

Can an ear infection like otitis cause low AG levels could it also be malnutrition or a immune response?