What are tactile entertaining/fulfilling activity suggestions for elderly woman nearly deaf & blind, with short-term memory loss/dementia?

A Fiddle Muff might be good. It's a knitted tube (muff) she can slide her hands into. Attached on the inside and the outside are a variety of small different textured items. My Dad has one made by a friend that includes a house key, silk flower, several interesting buttons, a large paperclip, a 1-inch squishy dog, large round bead, a piece of rope, jingle bell, and 2 dice. There are more I don't remember right now. It was knit from lots of leftover yarn so it's not only colorful but also many textures from bulky yarns, acrylic, wool, fine grade and so on. The opening on one end has fringe, the other is finished with a satiny blinding material. Some things, like buttons, are sewn directly to the muff, others are attached by string, cord or yarn.
We do 2 activities with it. Either "Can You Find The ______? " or I put his fingers on an item and ask "What's This?" He has good vision, but when his hands are inside he can't see what's there. And, since things are attached inside and out you can reverse it and have more treasures to find.
Your Aunt might enjoy those games or might just like feeling all around on the muff and discovering the various textures and temperatures of the attachments. Metals are cool at first but warm when you hold them.
I dont knit but there is a very active knitting group in the neighborhood that is happy to use up ends of yarn on these muffs. You can provide the trinkets to attach.
Enjoy!

Perhaps listening to her favorite music, singing together if your Aunt enjoys singing. I bought my Mom a robotic therapy dog (they make cats too). My Mom loves petting her "dog".

Hopefully others will come up with some other ideas.

Jenna

There are handheld knitting machines. I just saw one where you turn a crank and it does the knitting for you. I knew a woman who had special needs kids who she taught to crochet and do crafts. Her children went to a school where some of the students boarded there. She started a little "craft time" for them. She taught them crochet (still have a pumpkin magnet I was given) and whatever their "challenge" allowed them to do. Some had physical disabilities and this knitting machine was something they were able to use.

Can she crochet? My grandmother had low vision and was able to crochet by feel, it's more forgiving than knitting because there are no dropped stitches.
Play-doh or modelling clay?
If it is just hearing difficulty and she can still follow the story line of books you might find a DAISY reader or app works for her (I'm in Canada so I'm not sure how you would access that in the USA)

How about knitting but with the HUGE needles and the big chunky yarn? Would that work?
Hooking a rug?
A box or bin of the little yarn balls (the puffy things that you make decorations out of..not a ball of yarn) Just sorting them according to how they feel.
Poor vision aside would she paint..just colors on a paper or canvas? Might actually be pretty ..if not use white house paint and paint over it.
The other obvious ones.
Folding towels, sorting socks. (does not matter..just putting 2 together if you don't have enough socks buy a bunch at the resale shop. )
And...a project for a student for the summer, maybe someone is Scouts. Get her history, her memories down in a Legacy book. Se might enjoy talking to someone about her youth. How is it she speaks 4 languages? Was she born here? if not why did she or her family leave? Are there any family recipes that you need written down? I wish I had some of my Grandma's recipes!

I would imagine that having vision and hearing difficulties would complicate an already difficult situation of her having short term memory loss. Often, people who have memory loss also have something called Loss of Initiative. It means they have little or no motivation to start or continue with a project. My LO would color, but, only if she was supervised and constantly reminded to stay on task and encouraged to continue. If not, she'd put down the crayon and wheel herself down the hall. So unless, there's direct supervision, I would doubt she'd stay with it. Some people like to fold clothes. You might check out the fidget or activity boards and quilts that are available on websites for the disabled. They provide something to do with one's hands as it has interesting textures and shapes.