Simple answer: You can't tell how the photographer exposed the images and you won't learn anything about that from looking at the histograms of the processed photos.
Chances are that the photographer is shooting in RAW and that the photos are post processed quite a bit. In post you can drag the exposure (that results in a pushed histogram to the left or right) to compensate for an incorrect exposure. You can also recover highlights and push shadows to the point that the histogram bear no resemblance to what it started from. These procedures will of course reduce the dynamic range but the lower than RAW dynamic range of the generated JPEG will hopefully compensate for this. If done correctly you will not be able to tell how the photographer exposed the actual photo.
I recommend that you read How and why do you use an image histogram? to help you understand what a histogram is and how you use it to improve your photography.
Further answer: You can however get some clues of how the photographer might have exposed the shots. If the images have not been stripped of the metadata, in particular the information about metering and exposure compensation you can give you some clues of how the images where exposed. Of course this can be misleading if for example non-TTL flashes are used or the metadata has been tampered with so don't trust the information you find in the metadata with your life.
You can also look at the noise in the image to draw some conclusions to where the image have been pushed but yet again if someone wants to fool you they can easily cover this up by adding noise to the picture deliberately.
Regarding your note:
As to the fact that great detail is preserved outside windows there's nothing strange about that unless the lighting conditions vastly differ between indoors and outdoors. Shooting in RAW lets you recover highlights to a high degree. The fact that the white balance of his body seems off is probably due to the photographer incorrectly balancing the light sources (natural and artificial) in respect to their colour temperature.