Her brain has been wired from birth by said cult. I know from my own experience that God has the answers and that He speaks to those individuals who humbly seek Him. Mormonism is a big thing for those who follow the faith, so Sundays and the occasional event depending on how much she does extra might distract her.
She is showing a common attitude of distrust for "anti-mormon" material.
You need to repent and change.