Mom can't sleep or sleeps 4 hours one day and none for 48 hours then 6 the next. What stage is this?

According to your profile, your mother is 69 and lives in Independent Living? If so, how do you know exactly WHAT her sleeping patterns are? If you are listening to her version of things, they may not be the least bit accurate. I say that b/c my mother who has moderate dementia continually says that she 'never sleeps' but meanwhile, they tell me at the Memory Care ALF that she IS sleeping when they go check on her during the night. Her version of 'not sleeping all night long' computes to waking up frequently. I'd say if your mother truly was not sleeping for an entire 48 hours, she would be completely non-functional.

If your mother is able to use a computer at ALL, then her dementia can't be all that advanced, really. She can forget all sorts of things and still not be too far down the dementia road, it's impossible to say without a proper medical test and evaluation. I can tell you that my mother has no idea what day it is even WITH an Alzheimer's clock in her room blaring the time and day, yet insists she's perfectly fine and has no business being in a Memory Care environment. Everyone else is a 'stupid moron' but not her, speaking of not being humble or authentic. :( She was diagnosed in 2016 and here she is 4 years later, still doing relatively okay, but in need of assistance with ALL activities of daily living. She knows who I am but can't remember anyone's name, etc.

Here is a link to the stages of dementia for you to look at. You may also want to start thinking about the next level of care for your mother as IL will not be sufficient after a while; it becomes way too dangerous for a dementia sufferer to live alone.

https://www.dementiacarecentral.com/aboutdementia/facts/stages/

Wishing you the best of luck!