Dream about sister crying expresses your emotional needs and desires. You need to incorporate various aspects of your life. Your desires or wishes will be fulfilled. This is your shadow and other unacknowledged aspects of yourself. You are being catapulted to a position of power in which you do not yet know how to deal with.
Sister crying dream is sometimes an addictive relationship or habit in your life. You need to rethink or re-plan your course of actions and set yourself on a better path. You tend to over think things. It is a sign for the Self. You need to make some self-improvements in your life.
If you dreamt about sister crying:
The trick is to try and connect your mind with your heart, and not focus on one to the exclusion of the other. Then what you really feel deep in your heart will be more easily translatable into words. If you can express your deeper emotions, you can resolve many things.