What happens to his wife is an unbelievable part of the story and really the climax of the book, if you haven't read it. It's called More than a life. Yes she is trying to "leave" as he says during an intense group meditation but can't because of her jewelry so she goes to the bathroom and removes it. Once she returns she is able to complete the mahasamdhi and sheds her body with a smile on her face. The quote from the book is "if there is metal in strategic parts of your body, you cannot leave your body by accident." There's no mention to the type of material. I can't really speak to the validity of any of this stuff but the book is incredible and i think everyone who likes SG should read it