Up till now it seems that you have been experiencing his emotions, and sharing his thoughts, without his being any the wiser.
Harry Potter and the Order of the Phoenix
The reason why I ask is that I saw another example from Collins dictionary, which uses 'you' instead of 'your'.
We could have stolen the original from the warehouse without you being any the wiser.
So, I'd like to know if both 'his' and 'him' can work in this phrase? And any reasons?