Alice kidnapped the boys, but deep down she never even wanted them, she just wanted her husband and didn't want kids. Alice hates her kids and took them as a way of getting her husband back. The old man is the man in glasses we saw in the flashback, whose girlfriend shot herself. Thus, she cursed the sink to make people's true desires come true. In this case, she wanted the children gone but the father wanted to be with his boys without her in the picture.
In short, the morale is about realizing what you have before its too late, because like here, in real life there are no second chances.