How do we work out this forced "religious exposure"?

Let me just say how this got started.

My Mother has points in her life where she becomes much more religious. She starts going to church, listening to lots of gospel music, etc. She wants my brother and I to join her in going to church, but doesn’t ask me as often since she knows I’m an atheist, and has known for years. A few weeks ago, she told my brother he had to start going to church on Sundays, and bible studies on Wednesday nights. He tried to talk her out of this, and when it didn’t work, he came out about his lack of faith as well.

It did not go over as smoothly as it did for me. She says he still has to go, even if it is against his will. She says he needs exposure. My brother has been going to catholic school since first grade (His Father’s idea). He’s going into tenth grade now. She says Catholicism has painted the wrong picture of Christianity for him.

He has been going to these gatherings for a few weeks now, and he is of course, miserable at them. They always ask whoever doesn’t believe to raise their hand, and so, he raises his hand consistently. At one gathering, the speaker said, “If you do not believe by this point, you probably never will.” And then our Mother shot him a cold stare. My brother is greatly saddened that his Father, and our Mother can not accept him the way he is.

He has had plenty of exposure. He came to this point through his owns thoughts on the matter, and he is old enough to know the difference between getting his morals from a god, or being a sensible, kind human being without reward or punishment.

How can we get the point across that he isn’t going to be swayed by people gathering for worship? That if he were to ever become religious, it would be through his own devices, not it being insisted upon constantly?

Sorry for the wall of text, any views on this matter are greatly appreciated.