How do I explain hydrolized food diets to my parents?
So my cat has been struggling with overgrooming and itching for years now, he's been in a cone for about 2 years. a while ago the vet (after giving our cat diabetes from steriod shots) recommended trying hydrolized food. From how I understand it the way the diet works is he eats exclusively the hydrolized food for a couple months and if we don't see results then we know his itching isn't a food allergy. shortly after starting the hydrolized food diet I moved away to college and assumed my parents would continue the diet to see if it was the food allergies. I found out that they were giving him churu treats with his benadryl, which ruins the effects of the hydrolized food. I told them that and they agreed to only feed him the dry food and water. He doesn't like dry food generally, so I encouraged them to get a hydrolized wet food.
I'm back from college they have the cat on "the wet version of his dry food" which i have been feeding him. This wet food has recently been out of stock so I've been trying to find a suitable replacement so I looked up his wet food and found out it was not "the wet version of his dry food" but a novel protein style wet food made from duck meat. I never bothered to look up the food before because I took my parents at their word and I thought he was still on the hydrolized diet, but he wasn't. He was on the novel protein long enough that we know it hasn't changed his overgrooming and itching, which is nice, but also we still don't know if the hydrolized protein is effective or not because we never successfully did the diet. My dad said he and my mother talked and they're deciding to stop entirely with perscription diets and just let the cat live in the cone for the rest of his life, but I was trying to explain that we never gave the hydrolized food a proper chance and we should try a hydrolized wet food.
I don't have the money or the space to take the cat with me when I go back to college and I also don't have the money to pay for the hydrolized wet food myself, but making the cat live in discomfort for the rest of his life seems cruel. Rehoming is a possibility, but I don't know if I could convince my parents to do that (and honestly I don't know if I could do that either). I thought it might also be environmental allergies, as 2 years ago we found out a blocked off section in our attic was completely overgrown with mold and it was leaking into specifically my bedroom, where the cat spends most of his time. We hired contractors to replace that part of the house but the mold had been there the entire time the cat's lived here and he's 13 now. I know long time mold exposure messes up your body so we got air purifiers for all of the rooms he goes into, but as far as I can tell the itching isn't any better. Please, I'm so desperate for any ideas on the itching and overgrooming or advice about hydrolized food or literally anything. My cat has been miserable for so long, I hate that he has to live like this. I hate that he has to wear that stupid cone, that he's always scratching and licking himself bald and bloody. I hate that we've spent so much time and money on a bunch of dead ends.