I like the advice everyone has given. I have to ask, though, why you don't want to say, "I'm not telling you again."? I don't see why you shouldn't, especially if it isn't your job to make sure he knows.
After he has already asked twice and you've told him, including the location of the information, simply say (and plainly so you don't sound snarky no matter how tempting it is), "Write this down because I'm not telling you again." If he does it again, tell him why this time. "I'm not telling you again. You're wasting my time. I asked you to write it down and you didn't. This is no longer my problem as this is not my responsibility."