Using articles I sent him from FreeRepublic, he finally convinced her, but then came the problem of (a) finding a doctor willing to prescribe ivermectin, and (b) finding a pharmacist to dispense it. He found a doctor, who sent the prescription to CVS in Austin. CVS prepared the prescription, but then when niece went to pick it up, the pharmacist refused to give it to her -- and then cancelled the prescription so she couldn't transfer it to another CVS.
A year ago Texas passed a "conscientious objector" law so that a pharmacist could refuse to dispense a prescription (e.g., abortion drugs) based on personal beliefs. This pharmacist invoked that law -- but the law requires that the pharmacist name an alternative source, which this one didn't do.
My brother called the CVS legal department, and they said this was against their policy. They quickly revived the prescription and sent him to a CVS store in Houston, which filled it. He's now busy FedEx-ing it to his daughter.
Brother plans to take up the issue with the Texas Medical Board.