Does someone who holds Power of Attorney for another person have a fiduciary…

Does someone who holds Power of Attorney for another person have a fiduciary responsibility to the person’s heirs/beneficiaries (i.e., to save as much money as possible for the heirs to inherit) or is the POA’s responsibility only to the person for whom they are POA (i.e., making sure that person’s bills are paid and that he/she is well taken care of)?

We suspect that one sibling is exploiting our parents Mom is unable to care for…

We suspect that one sibling is exploiting our parents
Mom is unable to care for herself (memory disorder), Dad is easily confused and manipulated. Both live in their own house.

A few years ago, four siblings met to discuss care options, legal advice, etc. Unfortunately, one sibling decided to grab the bull by the horns and procure a family lawyer for our parents without our knowledge, excluding us from any involvement. She obtained power of attorney, and had my father sign a quitclaim deed (MA) giving her the lion’s share of our parent’s house. Also, she put her name and address as the primary on their bank accounts.

We always thought (and have some minor evidence) that our parent’s wishes were to distribute the estate equally. And while we were excluded from involvement in arranging for our parent’s care, we have evidence that we did seek this information.

Dad is expressing some doubts about the distribution, but he apparent fears retaliation from our sister (though no abuse is evident, other than possible exploitation).

We suspect the bank accounts have been drained and at this point we hope to at least get equal shares of the house. What can we do?

power of attorney I gave my mother power of attorney to sign papers for the…

power of attorney
I gave my mother power of attorney to sign papers for the sale of my condo because I couldn’t be there. The problem is that I never received a check for the sale from her. The deed was in my name but sher insists that since she was there to sign the papers, she gets the procedds from the sale. Is there any legal recourse I can take in order to recover the proceeds from the sale of the condo?