Chad's family may have bought into his proclamations, ideas, and visions (more or less), but I would guess they wouldn't have particularly endorsed his (and Lori's) thinking that it's a good idea to kill people whenever Chad and Lori felt it's suitable. Including family.
Personally, the more we're hearing from the witnesses, it sounds to me like ALL of this (INCLUDING the proclamations, ideas, and visions) was just a good ole-fashioned scheme to get money. These were people who, we are hearing, were continuously gasping for money. Always needing more. So they get creative with "ideas" no one else has -- and sell them to people looking for an idea and someone to make it make sense. They do podcasts, sell books, get followers, and hold conferences -- and eventually when that doesn't give them enough, it devolves into finding a way to make family "expendable" -- in one way or another, trying to cash in by deaths of those around them.