I've just gone to 24/7 care in my moms house as she almost burnt it down leaving the stove on. I've been in denial but no more. Short term does NY times crossword puzzles, drives with her aid, conversations in the present are fine with full recognition of family but her memory capacity is 5 minutes. Did not remember the fire dept was in the house half hour later. question is What to expect, she is on memory drugs, but seems she just hit the next degree of severity.
I agree with Jessie that it would be good to have a general check-up, in case anything treatable is contributing to this decline.
Most of us want to know what to expect next, but it is seldom as easy as looking it up on a chart. For ALZ there is a recognizable pattern. Look up the stages of Alzheimer's for a general overview. Not every individual with ALZ fits that pattern exactly. And other kinds of dementia have their own patterns which are often even less predictable. For example, wandering behavior is common in some kinds of dementia but rare in others. In Parkinson's with Dementia or Lewy Body Dementia it is unusual to lose person recognition.
If you know the type of dementia your mother has you can do a little reading about its progression. Just be aware that each case is unique -- and it is common to have more than one kind of dementia.