Adam casts Emrakul, the Promised End and resolves its trigger, taking control of player Nathan's next turn.
During Nathan's turn, Adam sees Infinite Obliteration in his hand. He casts it, naming some irrelevant creature that his deck doesn't contain (but still legal in format for choice legality). Now, even though Adam makes all choices of what and how many to find, is Nathan allowed to look through Adam's library and hand?
If Adam names some creature and just shuffles his library without searching, commenting “Failed to find anything”, can Nathan request to look through his hand and library?
The closest rule I found is 712.4:

712.4. If information about an object would be visible to the player being controlled, it’s visible to both that player and the controller of the player.
Example: The controller of a player can see that player’s hand and the face of any facedown creatures he or she controls.

Seems like information about library and hand contents should be visible to both players. But I'm still confused and need a little clarification.

While Adam is making the decisions for Nathan, Nathan is still searching the library, and Adam can't hide that info from Nathan, since it's information that Nathan would have access to. So yes, even if Adam is going to choose for Nathan to exile nothing, Nathan is still searching their library and hand, so Nathan will get to see Adam's hand and library.

Nathan Long
Magic Rules NetRep