At 18 he's probably suffering from Old Age. We had a Domestic Longhair that lived to about that age. She got to the point that she had trouble controlling her bodily functions, I.E., would actually poop in her bed while asleep, stopped grooming herself, couldn't jump, lost her hearing, and not sure about her eye sight. So no matter how hard it was we decided the best thing for her was to put her down. It's a tough thing to do, but there is such a thing as Quality of Life for our Fur Kids Too.
2018 Chevy 3500HD High Country Crew Cab DRW, D/A, 2016 Redwood 39MB, Dual AC, Fireplace, Sleep #Bed, Auto Sat Dish, Stack Washer/Dryer, Auto Level Sys, Disk Brakes, Onan Gen, 17.5" "H" tires, MORryde Pin & IS, Comfort Ride, Dual Awnings, Full Body Paint