I hope your Sherbert will be able to fully recover. If not, there are a few things you can change to accomodate having a deaf kitty in your home.
We have a deaf kitten. She became completely deaf and has permanant neurological issues due to a terrible infection she had as a younger kitten. Here is what we do to accomodate her disability:
We try to catch her attention visually before we touch her so we do not startle her.
If she is sleeping, we will blow a light puff of air on her or gently jiggle her bed to wake her up.
We have started using hand signals to communicate with her, but she has to be looking at us in order to respond.
We make her wear a jingle bell collar (hence her name: Jingle Belle) so *we* know she is underfoot/nearby and WE have to watch our feet because we cannot say "Move kitties, out of the way!" with her.
The jingle bell collar would also be helpful *IF* she ever accidentally gets outside. She can't hear us calling for her, but we would be able to her her jingle bell collar to find her.
PS ... I have also bought a small "locator", like a tiny remote I can attach to her collar. The other remote is synched with it and at the press of a button, I can locate her when the locator on her collar beeps in response.
I have not put this on her collar yet, I am try to think of a way to attach it so it can't dangle down and get dipped into the water bowl and/or accidentally activate the beeper on her locator if she wrestles with the other kitties.