"But he that shall scandalize one of these little ones that believe in me, it were better for him that a millstone should be hanged about his neck, and that he should be drowned in the depth of the sea."
"Woe to the world because of scandals. For it must needs be that scandals come: but nevertheless woe to that man by whom the scandal cometh." Matthew 18 6-8
Hmmmmmm............
15 years old is not a little one. And I doubt this kid believed in HIM anyway.
Look. If this kid was a saved Christian, than what he did was wrong and a sin, but it would not be enough to condemn him to hell. However, If he was not a saved Christian, than the point is moot, because he wasn't saved anyway.