The deed of sale would be listed in the county courthouse. If not too long ago, you might find it on TexasFile.com or another site or maybe the courthouse is online. Not much to be done at this point unless the surface owner wants to sell the executive rights back to you. If there is drilling, then you may get royalties. The executor’s name should be on the probate documents also filed in the county where the person who passed resided. You may need legal advice.