Because of Biden's pardon he can't be prosecuted. He is one of many political criminals that belong in jail. Its a waste of time for any senator to question him. Before Biden's pardon he was grilled by senators, and nothing ever happened to him. The only way he could be prosecuted is by a state level prosecutor, which would be one high mountain to climb. Biden knew he was a criminal. Its why he pardoned him. Fauci knew he himself was a criminal. Its why he accepted the pardon.
These hearings where senators grill political criminals is all for the camera, and for political pandering. Nothing ever happens to any political criminal. History has proven that.