Have you considered any horror films that weren't made in the past decade? Get a film that was made before the 1970s and you can be pretty sure that it won't contain a whole lot of gore or bad language. I know some of the young folk have no patience for black-and-white movies, but if your wee one is of a superior sort then maybe you could expose him to The Bride of Frankenstein
or the original King Kong
. Who knows, he might even appreciate the fact that they're very good movies.