My own fall away was cemented in a CCD conversation with a nun who agreed with my points of skepticism and was justified in taking the walk. Mom never said anything. Dad asked if I felt satisfied hurting her with my lack of catholicism which amused me since I truly believe he was an atheist himself.
My own Mom used to throw out poignant remarks about how she worried about my salvation. Finally I was forced to tell her that thing the pastor said to me that I'd been carrying around for so many years.
I told her, and then said that, if anything, it strengthened my spiritual convictions even as it burnt my view of organized religion.
I told her that the pastor's little fatwah made me feel as if I'd bought a car that turned out to be a lemon the first week and that the car company told me tough beans, and so while I still had strong spiritual beliefs, this was a betrayal by my own team and I was simply switching to a different "brand", that's all.
I think she finally made her peace with that, possibly also helped by the fact that, if I was in the area and she wanted to attend services, I would attend with her out of respect. Karen did the same, and she was proud to show us off to her pastor.