The purchase of the E1/2 of SW4 (80 acres more or less) is not recorded in the Tract Book. This indicates that the land was purchased from an individual and not a land office. I did not find this record in Deed Book A (dates 1833 to 1908) and did not have time to search other books.
A quick review of the Reverse Deed Book (where a land sale is entered by seller's name) did not reveal the name. I also checked Order Book 1 (if died without a will) and Will Book 1 and did not find any entry for the name. Be advised that none of the will and order books are indexed by name.
I would guess that the land was sold on or about the date after his time of death. Just speculation and I have no proof.
send your e-mail address and I will scan a copy of a plat book so that you can see where the land is located