if the kid likes Cradle of Filth I could really care less. He can listen to whatever the hell he wants to. To say that they are the most extreme band er whatever is an obvious understatement and you need to be exposed to more bands. I agree with the previous recommendation and download Soulseek or something. I can't stand Dani Filth...I listen to BM and can tolerate almost any vocals but Dani's are just...intolerable.
The most extreme metal I've heard is Axis of Perdition. That band is mindblowing.
Oh...And "Cradle of Fear" was, seriously, the worst.movie.ever
there is no argument. If you thought the movie was clever or took it seriously...there's no hope for you