Sorry to hear about Peedee's renal issues! We have a member here, growler, who is well versed in everything CRF, so hopefully she'll be around to give you some advice. My almost 18 yr old cat, Aztec, also has renal insufficiency but it's not as bad as Peedee's. All I've really done is tweak his diet a bit and added some Chinese herbs and glandulars to his food.
Did the vet mention anything about giving Peedee subQ fluids at home? It's really not that hard once you get the hang of it, and could help make Peedee feel better.
"To close your eyes will not ease another's pain." ~ Chinese Proverb
“We must not refuse to see with our eyes what they must endure with their bodies.” ~ Gretchen Wyler