I have some relatives who are in a "micro cult" ... basically just their household and their in laws. No one leaves the house, the children are "home schooled" (meaning they're completely uneducated) I have a 19 year old cousin who's never had a friend in her life, and she's told by her parents she has autism. They have absolutely no plan for her future, except for her to live in their house. Their 13 year old son is in the same boat as his sister, except he does have autism, but he's never gotten any help. They're very vicious to anyone who questions them, even using words like "blasphemy", and they do a really good job isolating themselves.
Everything's about absolute control, especially of the children. My cousins can't even read emails or have phone calls without their parents monitoring them.