The single best Christianity-debunking book I know of is W. W. Bartley's
THE RETREAT TO COMMITMENT. Unfortunately, judging by your mother's argument
that you presented, it would be way over her head. But it was written
against the subtlest and best of the twentieth century Christian
theologians and apologists, and I think it does a good job.
But there's ton of simpler stuff on the Web. Have you checked out all the
material at
yet? This is the best general collection I know of, if antichristian
polemics are what you want to focus on.
Nietzsche's THE ANTICHRIST is a lot of fun, too, though again, it might be
a little strong for your mom.
Eric Watt Forste <arkuat@pobox.com> http://www.c2.org/~arkuat/