My mother-in-law has FTD dementia (previously called Picks). Normally 3-6 times a week things break and a "catastrophe" happens. She can't explain how something breaks and does not know how to fix it but then the caregivers are stuck fixing it. We have now incurred over $17K in expenses in year. This week she pulled the water hose off the toilet and flooded the top floor and basement of the house, pulled the taps off the kitchen sink and stuck a duster through a fan (killing the motor). This is only the critical stuff...the ottoman that has lost 2 legs (not sure how that happened either), the table cloth soaked in a whole bottle of soy sauce etc. that she fixates on until it gets looked after can sometimes be left until later if we can distract her.
There is simply no way to control everything unless someone is supervising her 24/7. It sounds like you nor anyone else you know can do that. So I agree, get her help fast either with social services or a guardianship. In some jurisdictions the county will appoint a guardian if no one else is available AND if it's an emergency, they will actually step in the same day you file the papers to get the person somewhere safe.
I guess the answer to your question is that you really can't prevent her from wrecking stuff. The only way to protect her from herself and to protect the property is to get her into a place that treats dementia and supervise her at all times.
Your explanation of putting the duster in the fan makes sense as well. I don't have any fan configurations of that nature but I can easily see trying to dust without realizing the fan is running.
What I find fascinating is how this woman's mind works - she may have dementia, but she's still trying to be a Nicole Curtis! Bless her little DIY heart!
But yes, it is a call for intervention. That's why I suggested removing tools. I'd hate to think that she has any power tools in the house.
I imagine JeniMem's MIL was trying to dust the fan when she put the duster through the blade. She couldn't figure out the right way to dust it anymore. The toilet might have been running, so the perfect fix would be taking the hose from the wall. (My heart stops thinking of this.) Probably taking the taps off was only removing the handles. This could have also been a disaster if the water was turned on. Apparently she turned it off first. Good!
These are very good warning signs to me to step in before something worse happens.
I'm assuming you mean the refill tube in the toilet tank? That could be disconnected with some effort, but unless it's already detached from the overflow tube, it would take some pulling and yanking. And water stops flowing once the toilet has filled. At least that's been my experience, but I haven't experimented in detaching it. Maybe she was trying to change the whole flush mechanism?
I think taps might be a UK term; I think you mean what we in the US would call a faucet? If she unscrewed the filter or unscrewed the handles, that's easy. But I don't see how she could remove the faucet mechanism without getting underneath the sink and using tools for the removal, in which case there likely would be a lot of water spilling out unless the shutoff valve was turned off first.
I'm not trying to be nit-picky, just trying to understand what aspect of dementia and/or previous occupation might be contributing to these random acts of destruction. I guess the issue though is that's it's happening now and that's the main concern.
Was she a DIYer before she developed dementia? Or was she a builder, plumber, electrician, contractor?
Do you think getting her some play toys might help? Something like Lincoln logs where she can build and destroy with harming anything serious?
Regardless, I have to agree that she could be a danger to herself and shouldn't be left alone. Jessie makes a good point; action is needed now as guardianship isn't going to happen immediately.
While you're making arrangements, pursuing guardianship, or taking other steps, it wouldn't hurt to have a security camera system installed in her house, connected to your own wireless devices so that you can monitor her and call for assistance if something else happens.
You might be able to find a way to put little battery operated sensor devices on things such as the kitchen stove (close to the gas or electrical line), or other things that haven't yet been worked on.
If she has any tools, take them away - even the screwdrivers. I don't know how legs could be removed from an ottoman without tools, so removing them might narrow down the potential range of targets.
I just can't help thinking that this poor lady is acting out things she did before she became ill and really thinks she's performing useful tasks in maintaining her house.
To clarify, "caregivers" are my husband and I. She does need homecare but will not let them into the house as she believes she is normal. Taking her in with us is also not an option since she refuses to move and smokes like a chimney (my husband has severe asthma so it is a bad combination). We cannot watch her full time since we both work (just to note, the husband and I are not even 45 yet...she is 62 and that's the nasty part about FTD). There is no other family and she alienates any friends with the FTD behavior.
So my first suggestion is upgrade the amount/kind of in-home care she has.
And my second suggestion would be consider whether it is now time for a care center to keep track of her activities.
Have you discussed these behaviors with the doctor who is treating her FTD?