Your relative may have worked on their genealogy in a way entirely different from you. They may never have completed what they set out to either.
A maternal relative worked on compiling the descendants of her grandmother–my great-great-grandfather’s sister. The relative never completed her work. There is not compiled genealogy. But her notes and letters are extant and those items were a great help in actually completing her work. Her notes outlined all the children and grandchildren of her grandmother. The letters and envelopes helped me to track down additional members of her family–although the work was never finished.
Make certain you’ve reached out to all the extended members of your family to see if they have similar materials.