NC . . . I agree with your post.
I know there is at least one book (sorry--I didn't google yet) that teaches you how to teach a child critical thinking. So focus on that----not the particulars of the religion. Give him the skills to HONESTLY come to his own conclusions through his own abilities.
This one is good (recommended to me by Black Sheep).
You can pick it up in p/b at Amazon for 6 bucks.
http://www.amazon.com/Teach-Your-Child-How-Think/dp/0140238301
And KS . . . I don't think this was being recommended as a magic bullet re the current problem . . . but it will solve it, and any others moving forward. It's the best thing any Grandmother can do for a child . . . anywhere, anytime.