You're speaking with Dr. Michael Salkin. Welcome to JustAnswer. I'm currently typing up my reply.
Dilute urine will be the norm now. Darker urine is more concentrated as we expect in normal cats but in Chumley's case indicates dehydration. Fluids are the most important part of Chumley's therapy. Watch for an increased respiratory rate - greater than 30 breaths/minute - which would indicate overdoing the fluids.
Thank you once again, Alice.
If he's becoming progressively more uremic, he can demonstrate a change in mentation (mental status) which would manifest as appearing "stunned". More fluids rather than less might be helpful in that case but there reaches a point where no amount of fluids will help. The blehperospasm (squinting) you're seeing isn't related to fluid administration. Perhaps his head hurts - once again, due to progressive uremia.
Those are additional symptoms of worsening uremia.