I have way too much experience with this. Is it a male? Is he older?
Wet food all the time.
Force fluids, beef or chicken broth helps.
Are they sending you home with bags of saline and a needle to administer fluid in his neck?
He's a male who has already had the surgery to refashion his "opening". We try to have him on a strict diet but it's a multiple cat household and there have been lapses. So far sub-Q fluids haven't been ordered.
I appreciate your knowledge and concern, Sally, but we are hardly neophytes in cat care. The cat-lady is vigilant and our brood gets excellent vet care. No need for distant diagnosis or treatment recommendations.