P.G.
Is there a room in the house with a window she can look in and not be seen by him? I know when I dropped my son off at daycare, the thing that helped me most was when I had to talk to the director and then went back and looked in the room and saw my son playing happily. Then I knew he was ok. If she can do that, or if you can maybe take a video with a camera that has a clock on it so she can see what time it is, and video him after she leaves when he stops crying so she can see he's ok after a few minutes of bye-bye crying. :)