Legal advise, Help!!!

[Eric B.]

My grandmother sold my parents a home and in the documents it said if they ever sale the home her and her husband are to receive an extra 5k total. They are now selling me the home, my grandmother divorced that man and he has passed, and she now has dementia and has no clue who we are any more. Do I still have to pay her the money? Do I have to split it between his family and mine? My aunt is power of attorney so if she gets the money I know she will keep it for herself and his family we have no knowledge of so I'm at a loss, any way I don't have to pay these people who are technically involved in no deserving way? Thank you so much