I think one should just have to sit back albeit your knowledge of a terrible situation and get on with your own business since your not part of the show. No matter how well you think you understood them when you can’t really put yourself in their shoes, well, I reckon people live by there own decisions and they just have to live with it. No one can change someone unless he/she wants to.
So, for you dubiousorchid, just let them be. Someday, somehow, in someways, your folks will understand. You know He will find a way to make them. :-)