In this extreme example the family spiritual leader was a cult leader and the family a cult. This is a great story about cult like behavior in every day life Apple, Google, software engineers, psychiatry) and I believe the writer did say that some families behave like cults. https://medium.com/illumination/which-cults-do-you-belong-to-ce565c0fcb35

There's no way she believed that they could kill themselves and then achieve prosperity--this was all about her power over them and her own desire to commit suicide and take everyone with her. Family annihilation suicide exists with or without superstition. Here's an upliftiting story of mine about one such tradgedy being avoided: https://medium.com/illumination/the-presence-of-god-328581f65545

(note that it links back to my suicide attempt prevention geared stories and that is not the purpose of my linking it here though many might find them interesting)