In the US you'd have to prove they were negligent, abusive, deviated from the range normal parenting standards, and did you significant harm...something like that.
Being in a religion you didn't like is what it's going to seem to the judge.
Usually these discussions go nowhere....I've come to believe discussing suing or any other revenge/justice is simply a mental exercise to make us feel empowered over a situation in which we felt powerless.
So far I've never heard of anyone actually submitting a case proposal to a liability attorney to see if s/he will take the case. That's what leads me to believe this is just a mental exercise.