Validity of notorized document.
If I have a ”Power of Attorney” notorized in the UK, is it valid in the US? I am a US citizen. The Power of Arrorney is written specificly for the closing on the purchase of some land in the US.

Fighting a Power
At the present time my boyfriend and I are residing at his decesed grandmothers home. Is aunt has power of attorney and the house presently has a lien on it for the next 3yrs. A family member has to live there until that time and then they will have a chance to purchase the home. We have been living there for a year now and signed an aggrement with the family to take over the property and stay until the lein is up, and then purchase to keep the house for the family. Now the family has sent us a letter stating that they want another family to move in and us to move out. Legally can they do this even though we signed an agreement, and if we want to puchase the house can he and not have to move?

Who has control of the house after the death of the owner
Recently my great aunt died and had no will nor an excutor of her estate. One of her grandsons had power of attorney but I know that doesn’t supercede death. The house was in her name so who now has authority to decide what happens to the house or who get’s the house? She had one son that has died and a handful of grandchildren, only one of which is mentally capabable and responsible enough, but he doesn’t want it.