Well, over the past three days we've finally started to have some success with the litterbox downstairs!! I haven't had to clean up any messes since Sunday morning now. He's on a couple new medications from our vet, as well as a refill of his Metronidazole, and it looks like something is finally working. Last night he had a good solid bowel movement (not to get too graphic, but hey, we were excited!).

I definitely think he was going back to the area around the TV each time because it had become a habit and he could smell his messes there. We put the litter box as close to the area as we could without it being right smack dab in the middle of the room (or right in front of the tv, which needless to say would be a bit distracting for us). We also tried everything to get the smell out- first tried Oxyclean, then bought some carpet neutralizer stuff from our vet, and now we're using Resolve which seems to get the stain and the smell out the best. I'd like to get a steam cleaner at some point and use it all around the area to really get it super clean.

Thanks to everyone for all the good advice! Please continue to keep your fingers crossed that Stewie gets past this and becomes the happy, healthy cat I know he is!