I think this is a huge assumption on your part. My grandfather worked in the White House for decades and had regular encounters with the various first families and witnessed many personal things.
Not really.
He claims to have been posted outside the Oval. Well, many of the alleged incidents occurred in the second floor residence. Uniformed S.S. don't go up there except for one who is posted at the top of the stairs that lead up from the north entrance hall. Those stairs are toward the east end while the main private quarters are on the west end. Only S.S. members who are on the presidential detail goes past the Treaty Room entrance.