I am sorry for your loss.
Thank you very much for providing those screen shots. Too often people don't give us the detail needed.
That said, can you clarify who received those 1099-B's? You or your mother? or your mother's estate?
It is very unusual for tax to be withheld on a 1099-B especially if all that happened was the transfer of shares from your mother's name to your name as part of closing the estate. That is generally not a taxable transaction until you sell the shares in your own account.
Perhaps you should call the financial institution and ask them, especially about the 1099 that indicates "sold." Or check you statements/online account to see what happened on 9/02/2016 and 9/23/2016.
