I'm glad he's on the mend, I went through that with one of mine and he had to be syringe fed too, not just pilled, because there were no antivirals in those days, it had to run its course.
About the indoor thing: my vet once said that you can bring it in on your shoes so the only thing really is vaccination, and pray that your cat isn't one of the unlucky ones that gets regular outbreaks