I'm so sorry about Maggie! Please don't ever give up hope entirely. You just never know.

As for a new kitty, if you want an older one (I'm partial to them myself), then I'm sure that you can find one that's known to be ok with dogs. Shelters and rescues will often have that kind of information; especially on surrenders.

Good luck with your dad, and with Studley (I love that name. If that's not the right name, it should be!). And most of all, good luck with Maggie! She's in my prayers.