Any advice would be greatly appreciated

Hi all. There’s so much knowledge on here I’m looking for any advice or help with my little guy. I had posted a couple months back about chalupa. He ended having a tooth trim but never ended up going back to his pellets and hay. He remained on critical care but took to it very well where I didn’t have to force him. The vet thought maybe he had gotten picky because he would eat treats as well and gained all his weight back plus some. Fast forward 3 months.. 2 weeks ago chalupa got a nasty eye infection and the vet gave us oral antibiotics, eye drops and pain meds. The eye cleared up great. At the end of the medication chalupa appetite for the critical decreased. We went back to the vet. We were given gut mobility meds, probiotics, vitamin b shot and told to do tummy rubs. The first 3 days he did great picked up his appetite but now it’s went away again. He has had droppings. Today is day 4 of not eating the critical care. Last night I called the vet and we made a game plan to bring him in today for another vitamin b shot and if he’s not better by Thursday to do blood work, X-rays ect. Last night I was desperate to get something in him and could only manage to force 8 ml in with a one ml syringe. I feel so defeated. Today he keeps coming up to the cage to me as if he wants something but will no take any food when I try to offer it. Please help me help my little love! He means so much to me! Any advice Is appreciated! Thank you all.