Thanks again for the additional advice, and the website!! I made some changes to the litter box area and tomorrow I'm calling the vet. Is there a "he pees on the floor" blood-work-up that they do or do I need to specify what I want him tested for? And if specifically, it's a UTI, bladder infection and/or crystals, and diabetes/pre-diabetes? Anything else? Plus, of course, the psychological possibilities.
Disneymarie - I wish I had some advice to you! At least Tycho isn't ruining massive amounts of carpet or costly floors. I think we did use the Feliway spray before when we took my boys to my parents' house for a few months, with four male cats to deal with introducing (and reintroducing!)