Is the "someone" in ur profile the sister who assigned the youngest sister POA? Does the POA take sister to doctors? What do you mean by not talking to you. Is she holding back info you need for sisters care? Or not listening to ur needs. I am big on the person caring for LO should also have POA. Really need more info.
Please give us more information about your situation to enable readers to provide advice, e.g. What do you mean by "dual power?" For which sister and what is the nature of her disability? Why won't your sister with POA talk to you? Is a parent involved? Are there other siblings?
Usually the person who originated the power of attorney had reasons for choosing the person they have delegated. The originators would need to be of sound mind to add you as dual power of attorney or I suspect you would need to get an attorney and proof of misuse of power for you to be added if the person under care no longer is of sound mind.
Would you care to elaborate? When there are frictions in the family, authority under POAs sometimes becomes the battleground.
Is it your youngest sister from whom you're trying to get authority? For what reasons? Is she unable to manage her own health or finances? Or do you feel that she's not properly handling the authority she has, over whom? A parent? Another sibling?
Is there any diagnosed dementia involved?
Or is it that you're trying to get the power away from your youngest sister?
More information will yield more succinct answers.
Is it your youngest sister from whom you're trying to get authority? For what reasons? Is she unable to manage her own health or finances? Or do you feel that she's not properly handling the authority she has, over whom? A parent? Another sibling?
Is there any diagnosed dementia involved?
Or is it that you're trying to get the power away from your youngest sister?
More information will yield more succinct answers.