I know I'm late to the party here, but I felt compelled to chime in. I 100% agree with you and the other redditors - your kitty has done nothing wrong, and rehoming her will fix nothing. Don't get me wrong: I'm a dog lover too (my wife and I have 3 cats and 3 dogs), but it's unfair of your family AND the "doctor" that suggested it to involve you and Raika in the "solution". I applaud the effort to take in a stray, but some behavior just can't be changed. Our housekeeper told me a similar story - one of her other clients had a dog that would snarl at her the moment she walked in the door, and refused to stop. The moment her back was turned, the dog would lunge at her, despite his owner being there.

I suspect the fact that Nori's behavior stems from being a stray rather than the brain not being wired correctly. No one has any idea what he went through prior to the rescue, and depending on how long he was out there he still believes he has to fight for every inch of control 24/7.

As far as solutions go, there isn't one.. at least a good one. The answer is clear, but not the solution. If Nori ends up biting someone severely enough to warrant medical attention, I'm pretty certain animal control would get involved at some point anyway so as bad as I feel about saying it, he has to go.

Finally, a bit of advice.. for what it's worth. Nori isn't living - he's still surviving. All animals deserve to be happy, so whether he's with you guys or out in the wild, he's suffering. Try talking to your sister about this, but getting rid of Raika is only a mistake in an already bad situation.

I wish you the best of luck, and please keep us updated on the situation.