deed of sale (1988) versus deed of donation (1998)

My dad owns a deed of sale document from my grandfather dated and notarized back in 1988. As a sign of respect to my still living grandfather back then, he did not push through with the land title application because my grandfather and my aunt is still living on that said land.

Now that my grandfather passed away, we wanted to process the land title under my dads name, but unfortunately my aunt doesn't want to because they also have a deed of donation dated 1998 named after their daugther.

The question is which is more powerful the deed of sale or the deed to donation? does the dates when this documents are made matter?

Hope you can help us po, we have passed all our documents already. But my Aunt and her deed of donation is the only one that is getting on our way.

another thing po pala...we paid the taxes recently...because this was not paid by my aunt...the payment was under my fathers name