Hope he has enough money to lawyer up. The ACLU certainly could not care less about his Constitutional rights. Clearly, nor does the FBI or the fedgov.
He is 91 years old. He is extremely smart and understands bureaucracy. He has chosen to attempt the difficult, but not impossible finesse of the situation with the “I am one of you, and have nothing to hide” defense.
He may be able to pull it off.
I expect he still has contacts, maybe people that he mentored, in high places.
He has not been charged, and they have not taken most of his stuff. Yet.