When you tell a special friend that you worry about her and her family do they tell you you're wasting your time and...
Concern Over A Friend and Communicating it with her family.
The hardest thing to do when you are worried about a friend is to do nothing. Sometimes that's all you can do, but often you can.
If you can gather with your friends family in a non-threatening atmosphere, like a restaurant or a park, this will put people more at ease and everyone will be on an even playing field, so to speak.
I'm not sure what you're worried about, but whatever it is; health, safety, etc., chances are her family and other friends are aware there is a problem but may be in denial or just hoping it will go away on it's own.
The only thing you can do is kindly and gently tell them that you care about her and that you are concerned about her and why. If they are willing to discuss it, that's good, but if they become defensive or upset, respect their feelings and let it go. Chances are, even though her loved ones may shut down or get angry at first, they will start to think about the situation and many times will start to work on the problem as if it were their idea. They may even exclude you from the process of dealing with it, but that's ok - what you really want is for her to be healthy and happy.