Morale in the West Wing has sunk to a new low. In private conversations, Trump lashes out regularly at Attorney General Jeff Sessions with a vitriol that stuns members of his staff. Trump’s children, meanwhile, have grown exasperated with Mr. Kelly, seeing him as a hurdle to their father’s success and as antagonistic to their continued presence. Anthony Scaramucci, an ally of some in the Trump family, whom Mr. Kelly fired as communications director after only 11 days, intensified his criticism of the chief of staff in a series of news interviews on Wednesday and Thursday.