Our oldest senior cat is having issues...wandering, yowling for food (though the dish is full), and counter surfing although he KNOWS (as do all the other cats) that that is a no-no. He's getting thin, but keeps up with his grooming and likes to be petted. I took him to the vet a few weeks ago for his explosive (and toxic) diarrhea, and the vet said it could be IBS. The diarrhea has stopped, but he still seems like he's spacing out. Thoughts?