In my reply #5 I had misinterpreted a map: in fact if the Chanin Building is narrow-side on like this the view must be from further along Lexington Avenue.
After spending far too long on puzzling over where this photo was taken from, I have reached the tentative conclusion that it is from the roof (or possibly an upper parapet) of the Bowery Bank Building, directly across E 41st Street from the Chanin Building. This matches the information that your relative was an elevator operator at a bank.
The photo below shows the two buildings. The street cutting diagonally across the bottom left is Lexington Avenue, the Chanin Building is obviously the building in the foreground, and the ziggurat -ike building is the Bowery Bank Building.
The Bowery Bank Building was/is 240 feet high. The Chanin narrow tower starts at approximately
270 feet. I get the impression that the subject is looking down towards the camera, possibly because the parapet wall is several feet high. So I think would be possible to capture this view from the roof of the Bowery Bank Building, but I'm not 100% convinced about the geometry.
There is no evidence that the image is inverted since the jacket buttons look correct. The light is coming from the man's right. If he was sitting on the parapet of the Bowery Bank Building with the Chanin Building behind him he would be facing SSW so the sun would be in the west, suggesting that the photo was taken in the late afternoon.
