Hi,

. I personally do not feed dairy or plant products to my cats and dogs.
I would put this cat on a raw diet, organic if you can. A good vitamin supplement, and some iodine.
I feed rabbit, pinky rats, organic chicken ,etc. my cats go outside in the summer so they eat chipmunks, voles and mice. I still give them supplements. Because all these prey animals eat food from our depleated land.
Please consider a more natural diet for the cat. I think you will see some improvements.
Also try and find a homeopath and a holistic vet.