My dog's health worsened after vet care for his kidney failure

My dog was getting skinny over the past couple of weeks so we took him to the vet. They diagnosed him with kidney failure (which we already knew he had) and pancreas failure. Ever since his daily treatment over the past few days (IV treatments w/ electrolytes and minerals, antibiotics, anti-vomiting medication), his health has dramatically and quickly gotten worse. Before the treatment he was just getting skinny. But now over the past few days since treatment, he is not eating or drinking, lost a ton of energy (barely moves), etc. It's very bad and looks like we will have to put him down soon. ( I am wondering, why would his health have rapidly gotten worse after the treatment? The vet said it was possible that his health would have declined anyways. But in my mind there is no way that it is coincidence that ever since he had this treatment that his health went from 80% to 10% Please let me know, I know you are not professionals but I live in a country in Eastern Europe which is undeveloped so the general health care here is not as good. Thanks

There is no need to reply. I got the answer from another forum, the problem is his pancreas, which led to rapid decline. I do not know how to delete this post otherwise i would have done that

Hello!   I'm going to answer anyway, just because I have time.  It is impossible to tell the answer from what you told us- tests and examination of bloods etc would be needed - but pancreatitis or pancreatic cancer sounds feasible.  It is not uncommon for more than one system to deteriorate at once, or kidneys to suffer because of dehydration caused by pancreatitis etc.   Sending love and best wishes and peace to you at this sad time.

Ps and thankyou for getting back and explaining that you no longer needed a detailed answer.  That was thoughtful.