Great, this is why we have a constitution and bill of rights - he has no legal obligation to speak to them, and of course, if by accident he said something that was incorrect (“I had tuna for lunch” when he actually had salmon) he would be guilty of breaking a federal law, “lying to a federal officer”.
> Great, this is why we have a constitution and bill of rights - he has no legal obligation to speak to them
That's not at all true. Now, it may be true that it is not a crime not to speak to them, it almost certainly is a legal obligation attached to his employment and he quite likely will be fired for cause if he continues to stonewall.
Useful background info: “Don’t talk to the police” video from a law school class https://youtu.be/d-7o9xYp7eE