My brother's bible class was teaching him about "addiction"

[Aoi Magi]

I agree the religious brainwashing or any indoctrination for that matter, if not dealt with in the early stages, can become irreversible later on. But when you are talking about his thoughts on sex, those might not be religiously triggered. Most kids at that age can be shy about discussing sex and might retaliate in a similar manner, especially if they are introverted in nature. This should fix itself as he grows older and starts getting sex-ed+hormonal-rampage. If not, your parents are more than capable at handling it. Leave the sex talk aside for a bit and try to figure out his brainwashing level first, and if it seems serious, don't hesitate to talk to your parents despite what your brother says.