Listen to the victim and avoid casting blame.
Make sure you say: "You don't deserve this;" "This is not your fault;" and "I believe you."
Be willing to say that the situation seems dangerous. (Verbal abuse usually becomes physical at some point.)
Give the victim phone numbers of domestic violence resources, such as the National DV Hotline (800.799.SAFE; TTY - 800.787.3224), and in Covington and Butler counties, victims can contact YAP (334.582.1580), and shelters, such as Covington county's Bethesda House (334.977.1005).
Keep in contact and ask what you can do to help, but avoid telling the victim what to do. The victim has to be the one to make the decisions to stay or leave (and when to do so). Keep in mind that an abuser constantly tells the victim what to do as part of the control.
Encourage the victim to call 911 if there is any fear for one's safety. Not only does this bring much needed help, a paper trail will remain regarding the incident which could be helpful documentation at a later time.