Well, he's certainly notified now
For the sake of explanation for any seeking it, no, you cannot see who votes your post up or down. But if 5 people vote a post down, it gets hidden, so the point of the feature is to allow some Moderation democracy. If you think someone's post is inappropriate, down-vote it.
On the other hand, if you read something you think is good - particularly answers to questions - up-vote. It's a good clue to someone coming later with the same question if one of the responses gets a lot of +s.
cheers
RET
