Post sale of the property, what legal consequence arise

Hi, My father has purchased an old house in my native (and that’s the only property) around 2 years before he passed away on 1999. After that, it’s been in my mother’s name. I am taking care of my Mother since then. I married after 2002 and we (along with my mother) moved to a different town. I and my elder sister are only two children to my father. She is married before 1999 and has two kids (one son is elder) and staying with her family. She filed a case on that property 5 years back assuming I was trying to sell it. However, she did not fight in court and the case got dismissed because of non-presence from her side. My mother (3 years back) has made “will” and given GPA on my name after the dismissal of the case (also mentioning case dismissal). She is still with me. Now, I am planning to sell off that property. Since my mother is not well and not able to travel, I am doing this sale transaction using the GPA which my mother has given. Even though my mother has mentioned in her GPA that, my elder sister’s case got dismissed and with all rights, she is giving GPA to me to carry out all legal proceedings (even to sell), I have been told that my sister still has the right on the property. My question is, after the sale of that property, using that GPA, and when the purchaser is ok with the condition of the document, what kind of legal powers my sister will have post the sale of the property? Can she file one more case like how she filed earlier? Can court instruct to cancel this sale transaction? What if the purchaser sells this to somebody else? Or, if in case, she fights the case on me, does court order me to pay some part of the sale money to her (if yes how much percentage)? In case if I buy some other property after this transaction, does she has right on that property saying the new property being purchased using the money earned during the previous sale? Please help me to understand the legal consequences of this event. Thanks.