Can anyone find any instance in history when a President attacks his own Cabinet member? I don't even know what to say about this.
Andrew Johnson took on his own Cabinet. He was impeached, in part, because he fired Secretary of War Edwin Stanton after Congress passed an outrageous law stating that he couldn't fire a Cabinet Secretary without Congressional approval.
Woodrow Wilson got into a row with his Secratary of State, Robert Lansing, who suggested that VP Thomas Marshall should assume the duties of President when Wilson was incapacitated with a stroke. Edith Wilson, who was the real President at that time, then pushed for Lansing's resignation. Lansing was replaced by Bainbridge Colby, who had been a Progressive Republican who had become a Democrat as recently as 1916. There was a cartoon of Wilson pushing Lansing overboard that was titled "Dropping The First Mate".
Johnson, in his defense, was saddled with Lincoln's Cabinet, most of whom were disloyal to him. Lansing was a purely political spat. There were other Cabinet members who feuded with their bosses mainly because they were rival politicians whose appointment was based on appeasing a political faction and not on loyalty to a President.
All of this makes Trump's treatment of Sessions, and Sessions' willingness to take it, all the more baffling. Sessions was an early Trump supporter who stuck with him through the worst. He treats him like a pet he doesn't like and wishes he could find a new home for. Why Sessions hasn't told Trump to take his AG post and stick it is a mystery for this age, if not the ages.