My Friend Is Considering A Custody Case After Her Husband (separated) Left Their Two Children (2yo & 9mo) Home Alone For Close To Thirty Minutes.

This evening around 11:30pm EST, my friend was at work and stayed late to help out a coworker with a project. Her soon to be divorced husband was at their apartment watching their children. He claimed he was beginning to get extremely anxious about her safety and drove to her work, leaving their children at the apartment alone. After hearing about this, she considered calling the police to inform them about the endangerment of their children. To my knowledge, she has not spoken to any member of the law as of yet. Because of this incident, and a comment the husband has said before about leaving their 2yo (then, just months old) home alone to get groceries, she is now also considering bringing a custody case against him. She is worried about the case she may or may not have due to harsh words she has said to him in the past. What are her options? Should she inform the police about tonight’s incident? What documentation might she need for a custody case? She lives in North Carolina.