It was widely reported at the time. I'm surprised you missed it.
Well I’m patient. Give me a link.
Congress cannot impeach a President for firing his cabinet members. It’s a right inherent in the executive. The last time Congress tried that was in the Andrew Johnson presidency, and it was regarded as an unConstitutional power grab by President Grant and every administration since.
In case there is any doubt the Supreme Court ruled on that very issue in 1926 in Myers vs United States.
“Myers v. United States, 272 U.S. 52 (1926), was a United States Supreme Court decision ruling that the President has the exclusive power to remove executive branch officials, and does not need the approval of the Senate or any other legislative body.”