Hi, my 17 year old cat urinates upstairs (next to his litter trays’ on the carpet . He uses new areas all the time - I clean it with the appropriate cleaner and he just goes to a different area all the time, we bought puppy pads to somehow safe the carpet

. It started smelling the moment you walk upstairs. He poos in the litter tray but doesn’t pee there. Am at my wits end. Vet checked him and said he is just old ....
Has anybody please got any ideas ?