The gospel versus religion.
Being able to participate in worshipping the god of religion is no privilege at all. You might choose to let them keep their "privilege".
Did you know that your mom would find it impossible to pursue the "Good News" according to Paul, and remain a follower of the Watchtower Organisation?
You could "agree" to a family study of the book of Romans, and focus on the "free gift" of "imputed righteousness" (aka Justification) as taught by Paul. In time your mom will be unable to avoid comparing this with the self-righteousness (works-righteousness) common in the Watchtower.