It could be. I've always believed that dreams can give us insight into our futures so long as we know what to look for. So it could very well be a premonition so to speak. I wouldn't be too concerned about the rape portion at the moment... as it could have just been symbolism for his feelings for the girl. (One sided, not returned, taboo, forbidden.) However, I would DEFINITELY tell an adult about his feelings for her. Regardless of whether he acts on his feelings or not, that's straight up creepy.