Jeffs has been pretty unstable for years, even before he went to jail. People within his own movement criticized him ruthlessly because of what a whack job he is, not showing any of the leadership qualities his dad or his predecessors did.
There's a group in Canada that broke with them a few years back, a ton of men and women who obviously still believe in pre-manifesto Mormonism but disliked Jeffs.
In the FLDS, not Fundamentalism as a whole but this church specifically, sex and marriage are often used as means of control over the flock. Men being assigned wives depending on how well they do, women being reassigned to other men or unsealed altogether as punishment. When Jeffs went inside, he forbade sex between married couples, which shows just how unhinged he is because in Mormonism as a whole, having babies is the primary, if not the only reasons why human beings are on earth. To deny this is to deny God, but I suppose being inside and not being able to get some, Jeffs had to make his egomania manifest in the community as well. He had sex with male children but I doubt he'll enjoy being rapped in jail. That, or this is Lyle's way of getting around Warren's ban on sex, because lets face it, the only way that freakshow gains numbers is through baby making. People don't join them, not in any meaningful capacity. That and "Mormon Fundamentalism" has been broadened a lot since the turn of the century.