This is obviously false, if it were true we, humanity, would have never developed and accepted new ideas. If it were true we wouldn't have communist, we wouldn't have advertising or propaganda or marketing or most fiction books.
The truth is as usual more nuanced, yes, with some effort you can convince your father that the Earth is in fact not flat, just like with some persuasion and skill you can convince people of anything you want, little by little.
It just isn't easy or fast and you cannot make appeals to authority.