Awww...it's too bad Shadow had to resort to this to get attention, but at least it's working....hopefully. And hopefully your sister will follow all the instructions with the antibiotics. Seems like there's a lot involved here for someone who didn't even want to take the poor kitty back to the vet in the first place, but maybe she's also learning more about the cat and starting to actually care about her in the process.

Anyway, I'm glad to hear things are going well, please keep us updated on Shadow's progress.