Hi Christina. I'm going to offer a little advice based on my experience. It may be as upsetting to read as it is heartwrenching to write but I have told people this story before and it may offer you some comfort in a strange way.
I hate kidney failure so much as it took one of my best feline-friends away from me. Before I start rambling, I must point out that I have helped many CRF cats to live long and happy lives. They can live for years if it's managed properly. Read on if you want to and I sincerely apologise in advance if I say anything to upset you.
My little angel cat, Hope was diagnosed with CRF in 2006. The vets were really encouraging and positive and I did all they advised. I gave her a special diet, Fortekor tablets and all the cuddles in the world. She didn't want to eat and got really upset at taking her meds. She was so sad but I kept trying. She didn't respond and I was on the phone or at the vets all the time. She kept on going for about four months.
Then there was that one evening. She had been even more sad in the morning. She kept coughing and falling over. I rushed home from work and cuddled her. We fell asleep together for about an hour and I felt that she was telling me she wanted to go. That night I resolved to take her to the vets in the morning. Sadly, she went to sleep in the night.
I'm telling you this because I firmly believe with CRF that a sufferer will tell you how they feel in their own way. If you're close enough to Arthur, he will let you know what's best for him. If you feel he is fighting, let him fight and help him all you can but I think if you feel him letting go, be there for him, tell him how much you love him every night he's still there and don't feel guilt when he goes to play on the bridge.
You feel every emotion in the book with CRF. You feel intense love, anger frustration and sometimes people even blame the cat. These are all normal feelings and you're not alone. I wish I had known about Purrs when I went through it, I felt like there was no-one there and the vets were annoyed with me (in hindsight they weren't).
One piece of advice I was given was to keep a diary. Take pictures, note down appetite and general mood. It's very methodical but in the long-term may prove comforting. If you feel Arthur is letting go, you can look back and see how happy he was compared to now.
The saddest thing is letting nature take its course. The end of kidney failure is a very sad one. I won't go into detail, I'm already in tears but it's much kinder with a little help from the vet.
Like I said at the start, this is so difficult for me to type and probably you to read but there are people on here who've been through it and are going through it and you can call upon us anytime for advice and support.
Take care and I'll keep Arthur in my prayers