Owned Land and/Rights with no Taxes?

My husband’s father used to own a LOT of land in Midland. At the time of his death in 2011, we believed he had sold it all until an oil company came up with a lease for some rights in 2017 on a parcel in Midland.

I did some recent digging and have found multiple deeds for property in and around Midland, including the one where this current oil lease sits. These are exclusively lots (no known buildings) that were part of several subdivision developments back in the 1970s and 80s. Nothing that likely has any real value now except for more possible mineral rights (some showed some rights were included in these deeds). I show plenty he sold, but many show no further activity in the court records beyond his purchasing them, so I must assume he did not sell them and still owns them, so I was trying to figure out who was paying the taxes on these properties.

The problem is that the county tax website shows NOTHING in his name (or any known family’s name). I show more than a dozen properties that even the City of Midland had placed lot clearing liens on that were released back to him in 2017 & 2018. I spoke with someone there and they pull the released liens right up with his name, so they clearly still showed him as the owner of record.

I go back to the tax assessors office and again, nothing. I even called and spoke with a lady who says, again, there is nothing in Midland county in his name. This makes zero sense to me and I cannot reconcile this information. How can he own so much land (and some mineral rights, too) and there is no record of him owning anything in the county as for as the tax office is concerned? Is there some clause in there I am missing that empty lots have no tax? Can you suggest another way we can get a definitive hold on what he does and does not still own there?

PS: I am 1000 miles away, so I cannot go to the courthouse and am depending on their online records. Lady in the tax office said she needed a physical address, but most of the parcels have “description” but not addresses, as they were new developments at the time. The few physical address I came up with are not valid and do not show in the tax assessors site, either, so I assume they’ve changed the numbers since the 80s.

Suggestions?

Ha, again. I just found one such property that was FIL’s in 2002 but sold and the lady who bought the 3 lots already has an oil lease on the property with the same company who did ours. That is a big old ouch!! I wish we’d known that he still held property then and was just not paying taxes, maybe we could have helped more than we did. He was too proud to tell anyone, we had no clue. Oh well, live and learn. If all his property was still held from that time, all of his grandkids could have had a nice ride through college, at least.