Statesboro, GA, USA
I've got young kids. Crying 30 minutes is possible, and not out of the ordinary. I think shrieks and unabating screams might be different, and warrant some investigation. You could always knock and ask, apologetically, if there's anything you could do to help their family. At the very least, it might assure you that there's no real abuse.
You have to play this one by ear.
Self-interest and concern for others are both active in your thoughts and decisions. Pray and ask for guidance. You'll know what to do.