[Yossarian]

So, what was there to tell him until something factual was known?

Well, you could tell him

1. that there was a red alert,
2. why there was a red alert,
3. what was being done about it,
4. the status of his wife (for the sake of helping him keep his calm), and
5. the current whereabouts of the critical members of the government, especially if they had been moved due to the alert.

This is pretty reasonable.....

[Ursus arctos horribilis]

So, what was there to tell him until something factual was known?
Well, you could tell him

that there was a red alert,
"why there was a red alert,
what was being done about it,
the status of his wife (for the sake of helping him keep his calm), and
the current whereabouts of the critical members of the government, especially if they had been moved due to the alert.
This is pretty reasonable.....
"

In short: Mr President, we have a report the sky is falling in DC and people are panicking in the streets, what are you going to do about it?

I don't think so, responsible people act responsibly.