Right now all of this is new and a change in routine for both you and Claude. Some days will be better than others.
Try to establish a routine, a round about same time of day for meds and fluids, and be as calm as you can...Claude is going to pick up on your emotions. I used to just be matter of fact with Patrick, and am that way with my current cats with kidney issues. It's not our whole life or day, just things we need to take a moment to do, once it's over, it's a kiss and a snuggle and we go back to our usual activities
Once Claude is better hydrated, and his levels start improving, his appetite will improve..in the meantime, do whatever you can to get him to eat. If you have to "prime the pump" - feed him a bit of baby food off a spoon (yes, it's pure protein, but the bottom line is no food, no cat...get him to eat anything if he's totally stopped) - like gerber second stages beef or chicken or turkey (has no onions added, is just the meat and maybe a bit of corn starch).
Try warming his wet food, for pills, you can try making a little meatball with the pill hidden inside, or get a pill gun to use to gently and quickly give him a pill.
Visit the jmpeerson food lists (in the initial posts in this thread) to find a variety of canned foods Claude might like - you can look for the lower phosphorous foods, and lower protein, though I've always concentrated more on lower phos in the foods I offer.
You can also try making a bit of plain chicken broth, cooling and offering that to him - to get a bit of flavor that might stimulate his appetite as well as sneaking in more fluids.
The fountain is a great idea, it should help. Others not only have a fountain but place water bowls in several areas of their home - wherever the cat will stop and take a drink
hope some of this helps...but truly...take a deep breath, love up Claude, and you two just cherish every day you have, and do the best you can.
Tears can come (hopefully years from now) later.