Stage 4 kidney disease advice

My sweet, approx. 15 year old guy was admitted to the hospital during his annual exam a month ago, when his lab work came back reflecting that he was in kidney failure. Since being discharged his creatinine, which, when he was admitted it was 10.8, and when he was discharged it was at 2.5, keeps creeping back up, and we’re now approaching stage 4 (currently at 4.8).

I’m looking for advice from those that have experienced, or are experiencing, this on anything you wish you had known, done differently or things that worked well (beyond the things recommended by the vet such as sub q fluids, renal diet, etc.) at this stage.

While we’re not quite at the end yet as he seems to still have a relatively good quality of life, I’m also wondering what creatinine levels looked like at the time you had to make the difficult decision.

It has felt like an emotional rollercoaster as he has good and bad days, and so I’m also looking for any advice on dealing with anticipatory grief.