On March 8, as the virus was spreading, the Murdoch family called off a planned party out of concern for the patriarch’s health, according to a person familiar with the cancellation. There were about 20 people on the guest list.

The celebration was to be held at Moraga Vineyards, the sprawling estate in Bel Air, Calif., where the elder Murdoch has been spending most of his time with his wife, the model and actress Jerry Hall. Mr. Murdoch bought the property for $28.8 million in 2013.

The person who told me about the canceled party did so to highlight the disconnect between the family’s prudent private conduct and the reckless words spoken on air at their media company.

The canceled party is perhaps the most glaring instance of the gap I wrote about this week between the elite, globally minded family owners of Fox — who took the crisis seriously as reports emerged in January in their native Australia — and many of their nominal stars, who treated the virus as a political assault on Mr. Trump, before zigzagging, along with the president, toward a focus on the enormity of the public health risk.

Mr. Murdoch is in good shape for an 89-year-old, people around him say. But he took a bad fall on a yacht in January 2018, an incident that rocked his empire, and he no longer regularly takes control of his newsrooms as he did a few years ago.