I understand how tough it can be trying to help someone who is so incompetent as something so "basic"; believe me, my father has been trying to help me learn stuff like this for a while now and the frustration on his end is pretty great
But it is as you said:
A child with self esteem problems needs to be nurtured and guided with discipline but lots of compassion. She's really like a child in this respect but, well, she's old and no one's got the time or motivation to spend time on her beyond a few hours or days like her friends have done.
She might be old, but that doesn't mean she's going to miraculously get it all figured out because she's an adult. From what framework is she supposed to start? If the way you describe her is true, how do you expect her to understand the way such things work? And i don't mean know, as in knowing the things you tell her that come much easier to you (seemingly), i mean
understand. Simply because she is an adult? Remember, you learned this stuff too, at some point, and I'm sure it didn't just happen. You were privileged to learn such things at a more opportune time than she.
You wouldn't throw anyone who has never swam before into a pool and expect them to figure it out, regardless of their age, so why the condescending attitude? What exactly will that fix? I would examine that more, if you really want to help your mother it wouldn't hurt you to actually reach out and HELP her and respect that learning to do such things takes time, especially as one ages.