I think you submitted your question early.
Either way, a cat that is hiding is usually a sign they are unwell. Cats tend to do this when they aren't feeling well. I suggest you make a trip to the vet in the morning.

I took Casper to the vet yesterday he had a blood test done, results are advanced Kidney failure needless to say we are distraught with the news that we will loose him.. no further treatment but love in the final days ahead

I'm sorry to hear about the news. Give him lots of love.