One question should be, does she want to learn braille? Many adults who lose their vision later in life don't learn braille, with all the new accessibility technologies available. Some do learn the basics (Grade 1), which is the letters and some punctuation.

https://hadley.edu/braillecourses.asp

Here is a link for some braille courses.

Does your mother use a PC, or an apple? Does she use an iPhone/iPad? Apple has VoiceOver built into pretty much all their products now.

https://www.apple.com/ca/accessibility/mac/vision/

If she has some vision, but is losing it, she should consider talking to her state rehabilitation center as well. They can start teaching her some of the skills she would need.

I started with this... $1

And a really awesome intro book. It’s for adults learning Braille, which is perfect. $1

as to learning Braille I hope it's what she wants because Braille if you are learning it to read it is incredibly difficult due to all the contractions and short forms, I would suggest a class if you can find one from the local college or something.

As to advice you can give and ways you can help just being there for whatever she needs even if it's as simple as finding something in the kitchen or walking around the neighbourhood will be great ways to let her know you are there for her.

Look up described television and movies together of some of her old favourites or your new favourites, Netflix has described captioning where the narrator describes all the action on screen, and several cable shows have it depending on how easy your converter is to figure out.

Second vote for Hadley. You’ll need a DTB player to listen to the course. They’re free from the NLS.

There are some books that teach her about Braille and what dots mean what letters. The National Foundation of the Blind (NFB) has books for people just starting Braille. You guys can call them or email them with some questions about what books she might like to read. The NFB also has technology that will help her see her books and or they have audio books for her to listen to.