TiaS is correct about the Mormon mafia. They controlled access to Hughes up to his death. They kept Hughes drugged up and exploited their connections, just like how Boreman controlled access to Hitler. If you control access to the leader, it makes you very powerful as Speer and Goering found out.
Hughes did it to himself letting the Mormons get that close to him ~ then, of course, there are books about how they handled him after that.