If someone tells you to listen to a song, listen to it. It may be the worst song you have ever heard but they wanted to share it with you. That is really special. If it makes them feel a certain way and they are so adamant about you hearing it, take 5 minutes to hear it. It shows a lot about someone.
Be a good friend. When your friend leaves an abusive relationship, delete/unfollow/unfriend their abuser. Don’t give them anymore activity. When they leave, leave with them. Be their support system. You cannot be neutral when someone was abused.