I can maybe help on the force feeding. I had a cat that went into liver failure and I had to force feed him for 6 wks until he was recovered enough to want to even look at food. I refused to allow a feeding tube - too many complications with them, plus anaesthesia - so I went the syringe route.
It is a mess, and the cat will be furious/upset but it has to be done if they won't eat on their own. I was force feeding small amounts 6-8 times a day. It was the only way to get enough food into him. I'd force feed the slippery elm about 30 min in advance so the food didn't come right back up (only needed to do this part twice a day). I ended up watering down canned cat food. Get whatever has a smooth texture and works for pancreatitis, since that is the current suspect. Add water and mix until it will pass easily
through a syringe (you need a high capacity syringe, you don't want to have to re-fill). You do not want a blockage and have to force it through. Think the Vesuvius of cat food
Wrap the cat tightly in a towel or other tough/thick material with only his head sticking out. Take care to trap the legs so you don't get scratched. Even my total mush of a cat fought and accidentally ripped me up a couple of times trying to get away. Cradle the cat on his back in your lap, hold his head as best you can with one hand, and insert the syringe in the corner of his mouth. Slowly squirt the food in so he has time to swallow. Try to get it past his tongue and into the back of his throat so he has little choice. It may help you to gently hold the jaws closed around the syringe, it did not help me and just seemed to upset my cat even more, if that is possible. There will be head twisting and spitting. Sound and fury. Food will get everywhere, including all over you. Try to estimate how much food went down the cat as opposed to everywhere else and adjust the rest of the feedings accordingly. The most important thing is to get enough food into the cat that he won't loose weight quickly - that's what seems to trigger hepatic lipidosis.
Good luck. I hope you get a positive diagnosis soon and that it isn't FIP. Had a cat with that, too
. Picked it up at the vet, ironically enough.