I think to save them, they need the help of counsellor... or somebody to help them talk and unwind and understand each other more into this sex thing. BTW, I'm serious and I'm not joking

erm.. I'm also a Christian... but maybe a very open minded one . I assume both your friend and fiance are Christians? Well... actually... from religious point of view... I guess they'll be told no premarital sex the point is.. still haven't married. but from professional's point of view... try to get more info about that counsellor first. at least.. there's a counsellor, but make sure it's a proper experience one. you can try ask our fellow LYN forumer for help all the best and wish your friend and her fiance a happy wedding in the end