The right of offset is a matter of state law. It can be enhanced by contract terms. Your attorney can give you the specifics in Texas. However, I'll bet that the answer to your question is the same as the one before for the same reason.
In general, the right of offset requires a "unity" of ownership; i.e. the person who owes you money has to be the same person to whom you owe money. In short the debtor and the owner of the account must be one in the same. A decedent's estate is not the same person as the decedent. If you want to be paid, file a claim against the decedent's estate.
P.S. There are few cases that are easier for a plaintiff's attorney to win than those generated by a bank improperly exercising a right of offset. Against a widow when this much time has passed? If you mess this up you're toast.
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In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.