On a related note, when I were a nipper my Dad hated me playing the guitar in the house and didn't really understand any of the Rock / metal thing at all. I wasn't allowed to buy myself anything more powerful than a 10w pratcice amp and some shitety 2nd hand squire. It wasn't till I left to go to College that I really took up the guitar as I could play it for more than 10 mins without getting a bollocking :)
However, (forward 15 years) two years ago I bought him a Led Zeppelin DVD for xmas. He'd just got himself a surround sound system and within 10 minutes of listening to Page et al it was on max volume and he was hooked. He just bought himself a guitar festival DVD with Steve Vai on it, and now he wants more METAL. He said the next time me and the wife visit him, I have to bring my amp and guitar too and make some noise!
Lesson: Rock always finds a way :)
But as Kilby says, don't push it ...