Thank you for the opportunity to help you with your question!
If you have firm evidence that a family member is not in a safe environment then it is your moral duty to notify the authorities of the situation. However, if you only PERCEIVE that it is unsafe then you may be crossing a line between between family matters that are really not your business. So, the way to handle it is to privately call certain help organizations, such as the rape crisis hotline, for example if you suspect that a family member is being unlawfully abused. Get the opinion of professionals before taking matters into your own hands.
Please let me know if you need any clarification. I'm always happy to answer your questions.