I had two cats for years and one (11) passed away last year. The one left is now 11. He is lethargic, barely eating and drinking and always looks so sad. He recently had a case of diahrea. He was an indoor/outdoor cat until 2 years ago due to hawks and coyote where we now live. Is this a sign of any illness/disease or is he close to passing away? Please note that we cannot pick him up as we took him in when he was a stray cat. So we cannot go to the vet. thank you in advance for your assistance!!!!