@Jnbmom wrote:Well I will try to make this as short as possible lol
My MIL along with DH have Alzheimer's, he is just no short memory at the moment, she is much worse.
A few years ago one of my SIL moved in with her to "take" care of her back then she was fully functional, well now that she is not she can't handle her or take care of her . When she moved in she had my MIL put everything in her name and I mean everything house property vehicle and banks accounts 😡
Well we have agreed to move in with her so I can take care of her , it also gives a purpose for DH and I think it would be a good fit .
SIL is moving to Missouri and building a house near her daughter ( just insight to her, her first builder outright quit) shows how overbearing she is .
We have a lawyer that is going to put everything in a trust and my other SIL as executor as when his mom passed everything will be divided by three as his mom wanted . My SIL agreed to get everything out of her name EXCEPT the banks accounts 😡 My other SIL lives right next store so she can help as well .
I don't want to be on the accounts I want other SIL and his mom on them and she can handle finances of house and we will split utilities and food etc no mortgage own outright .
Now SIL who still resides with her has a POA she printed on internet lol. and since his mom can't see and really can't sign anything not sure how we get that changed lawyer stated that we could deem her incompetent but really don't want her to go through that .his mom also can't even sign her name
I think we have the house and property all squared away waiting on final papers from lawyer but she is really pushing to stay on bank accounts (200K) roughly . Her reasoning is what if something happens to other sister that way she would still be on account, can she set up for her or hubby if that's the case to be beneficiaries?
I'm so sorry you're going through all of this. 
I'll let others chime-in about the legal stuff, but due to being on a bank account with an elderly loved one myself I can understand your concerns/frustrations with your SIL who doesn't seem to want to let go.
Here's a thought... there's not much reason to fight over the bank accounts, since as long as your MIL hasn't been deemed incompetent she can simply transfer the funds herself to another account that doesn't involve the problem SIL. If SIL tries to say MIL isn't competent to do so she might indict herself in the process (if MIL can't transfer funds, she couldn't agree to POA, etc).
Of course you'll definitely want to check with a lawyer, but the bank accounts might not be as much of a problem as you think (other than the fallout from an upset SIL, of course). As for the POA, it can be revoked with a notorized form (very similar process to setting it up) - again, lawyer stuff.
Side note: In my family's situation we hesitated too long to get the lawyer involved, and things almost got really complicated before hospice was brought in and a few weeks later she passed. That hospice period (and the months before) were precarious, since had something beyond paying routine bills come up we had nothing legal indicating she was incapacitated.
