How do I communicate with my partially blind, mother (96) who in the last two weeks became totally deaf?

OK, you say her hearing has deteriorated in the last two weeks, why? Has she seen a doctor about this? This could be something as simple to treat as wax build up or as complex and untreatable as stroke related nerve damage and needs to be investigated. If you can restore even partial hearing it would be so much better for her.
As for writing, some people have better luck using a screen where the type can be reversed to white on black and adjustments can be made to brightness and contrast.

Irish, since your Mom is almost blind, she has learned her way around her current facility, thus in her mind she know it is so many steps to here and there. Moving her would cause a lot of confusion.

My Mom [98] had the same situation, she developed macular degeneration which made it very difficult for her to see, plus her hearing was disappearing even with using hearing aids. Regarding the font size for reading... what size is your Mom's writing? If it is normal size, then use an one step up size darker font for reading if your Mom has macular. See if that works.

My Mom refused to move from the house that she and Dad share, and I didn't realize until now why she dug in her heels.... she knew every inch of that house and she wouldn't allow Dad into the kitchen except to eat, she didn't want him moving things around in the refrigerator or the cabinets.

My Mom also had fall issues, but that was because she refused to use a walker. She didn't want anyone to notice that she was aging.... [sigh].

You certainly do face a challenge. As I read your post, I was trying to remember how Helen Keller was able to learn.

I believe it was in part through touch, but I don't know the specifics.

I'm wondering if your mother knows Braille, and if not, I would contact a Braille or charity for the blind and ask if there's a way to teach someone who's also deaf.

I think Braille is the best bet, but just don't know how, if, it could be integrated also with deafness. I would contact an organization for the deaf as well though.

How horrible for your mother - to be totally cut off from communication- even if she has difficulty making sense of it. Is it possible to use a large screen laptop to bring up images of the new place - and perhaps a large magnifying glass? My hubby is a tech geek and can plug in a laptop to a tv - can someone do that on a large flat screen and show the new place? I don't know - just brainstorming. Does your mom like it there? Does she have a routine that would be hard to break from? What about friends there? And of course there is the possibility of adding a private caregive. But I know that can be expensive when one is already paying AL costs.