Where are you guys getting this from? Not doubting you just wondering.
It was all classiified. When he resigned he lost his clearance. He was “read off” all the clearances he had and can no longer divulge any classified information he knows without permission.
What power a Congressional Committee has to impact that I do not know.
If I was him unless I had something signed by the DOJ, DOD, DCI, CIA, etc., I’d keep my yap shut.