Don't think this shows she loves him or religion more than the other it shows she loves both her religion and her son. His mom cried probably because she feels guilty or at fault because in her eyes her son isn't following into her and her husband's belief and she might feel responsible that he hasn't followed her path and maybe blaming her every action. I don't think she is disappointed in him, she might be disappointed in herself. OP said his mom didn't tell his dad which is bit surprising as I would expect her to just immediately tell dad and dad would get SUPER pissed but she let him alone probably in hope that he finds the religion himself one day.