I am so sorry for your loss.

My Filou has this kidney disease too. He is nine and we had his blood checked routinely this year- this is how we know.
It is not sure whether he will live as long as Kennyken did but I hope for another 2 or 3 years.

I cannot tell whether it is better to know - which means that sometimes you start crying by looking at him and sometimes you cherish every moment - or better to be surprised - which means the last years were happy and normal but you had no time to say good bye.

My heart goes out to you.