Hi Roby22, Glad to hear that your kitty is doing somewhat better
My younger kitty, Samson, was very similarly sick to what your kitty seems to be going through.
Has your vet done an ultrasound? If not, he should definitely do an ultrasound of the stomach, pancreas etc. I had been in 3 times with my Samson and he had lost some serious weight, would not eat etc. He acted like food repulsed him. My vet had done full blood work, taken an X-Ray but could not figure out what was wrong. Finally he suggested an ultrasound, which is what saved my cat's life!
It turns out he had a hepatitis feline pancreatis. This means that the fluids in the pancreas aren't coming out as they should and instead of functioning within the pancreas, it is doing so out of the pancreas. This can potentially lead to massive organ break down.
If the ultrasound does reveal this, my vet put him on an IV and antibiotics, then Amoxil, Denamarin (liver supplement); Ursodiol (specially compounded for him); Metronidazole and Famotidine. (Just sharing in case it helps)
If you have to assist feed him, just give small amounts at time, 1/2 of a tablespoon, once every hour, then *slowly* build it up as he can tolerate it. Also try just opening a small can of tuna and just let him have the juice and small bits of the tuna. It was the one thing that Samson would eat on his own when he was sick.
By the way have you ever had to assist feed a cat before? If you haven't here are a couple of tips that might help. This is what my vet recommended.
With your hand gently cupping the top of his head, place your thumb and middle finger on each side of his mouth at the corners of his lips. With your fingers gently pry his mouth open by squeezing inward against his teeth. However, make sure not to press against his lips as this will hurt him.
Approach his mouth from the side sort of sliding the syringe into the side of his cheek and then push a small amount of food in into the side of cheek, that forces them to chew it in. (the way a squirrel or chipmunk would).
Ask your vet for the biggest syringe he has, the bigger syringe makes it so much easier to push the food through, remember though, very very small quantities at a time, almost half a pea size and then up to half a tablespoon per sitting or up to a tablespoon if he tolerates it. When you see that he is starting to resist the feeding, just stop, don't push it. Your baby just needs some time for his tummy to adjust to the food he has just taken in.
Don't give up, your baby *will* get better! And please keep us posted.
Hope this helps