My mother’s dementia is so bad that she can’t remember to push the button for help. How should we handle this?

She should be moved to a more 'secure' area where she can be more closely supervised! Assisted living is ok if just require 'some' help with daily activities. As you stated, if her dementia has progressed to where she doesn't know HOW to call for help (with the lifealert) then she needs to be where staff supervises her daily activities. There are 'sensor pads' that can be put in to tell if someone has fallen out of bed, or for that matter even if they get UP out of bed, so she doesn't fall and hurt herself.

Ask the facility about more secure housing options. And follow up with the facility to make sure that they are aware of her limitations.

Does she hurt herself when she falls or does she simply get herself up and go about her business? The reason I ask is that my mother-in-law also falls once in a while in her apartment in her living asst place, but just gets herself up. She also never remembers the thing that hangs around her neck 24/7 to call for help. In normal conversation she will let it slip that she fell. When I remind her that she has the alert necklace on, she just says 'I do?' So I can't help you with this problem, cause we're in the thick of it now. But as long as my m-i-l still can get up, and doesn't hurt herself yet, I guess we're okay. They do check on the residents everyday at her place though, either by reminding her of meals, take pills, etc. So it's not like she will just lay there for days like she would've when she lived alone.