I would love it if my friends got hold of my email details. Do you know I think it would be a right old barrel of laughs if they also got my bank details and my pin numbers.
Oh the fun we would have.
100% trustworthy people don't want to get access to other peoples email.
Obviously just some sort of practical joke or whatever, however I think the whole invasion of privacy outweighs you friends requirement to humour himself.
Didn't say he had bank details on there, however how would I or you know what he has in his emails. I was being sarcastic.
If he is a friend, then you will have access to his computer, maybe at times when he is not there.
Try Googling for software, I am not going to tell you what it is, but this software will give you all of his passwords and personal info that he puts in his PC.
If you do not have access to his computer, then he is not a friend and you have nothing to worry about becuase you will never get to play your little joke on him.