I think all to many parents use religion and the child's openness and need for God as a way to try to control with guilt. I think parents don't get how cripplingly guilty children can feel or how hard it is for a child to tread the path of virtue.
So there are a lot of adults who still are essentially pathological about guilt and God. You may hear from the pulpit of the marvellous love of God, but when yu get home you get, "How do you think Jesus feels when he sees you doing something like that?" That's going to leave a mark! I will join my prayers to yours. I also would like your mother to trust in Jesus.
Bless you, dear MD. Thanks.