General Power of Attorney

My father gave me a GPA in 1996 to take care of a property, which was purchased by on his own. This is a dispute land and there are many cases of all category of courts and many verdicts have been passed on this land during the last 30 years. This GPA execution appointed me as representative, allows me to do all matters like to sell, mortgage in any manner, lease out, assign and receive the consideration involved, manage,loan from any source, grant, convey, manage, and put up any structures, demolish or remodel in the said land and repay the said loans and liabilities and execute the necessary deeds and documents for the purpose and register the same at any Office of Registration and execute all papers required for the purposes on our behalf in the same manner as we are entitled to do with it personally. This land was connected with a dispute between my father and a watchman. My father passed away in the year 1998. Now, I am taking care of the all cases and other matters related to this land. My question is that is this GPA is still valued or not?.