In the context you gave, both are verbs and can be used interchangeably. "Help out" seems a bit more casual in my opinion. You might say to a friend, "Could you help me out?" If you are in more urgent/desperate need of help, you would just say, "Could you help me?" or even just a command like, "Help me." The father in your example would most likely say, "Come help me" or "Help me." I hope that helps. Best, Anne