Of course, from the perspective of a friend, we want some magic words to make it better, to make it hurt a little less. But I think just being there is more important than what you say. Being there shows that you care and that you want to help. Normally, the one hurting, the one that needs to talk, will start the conversation without much help. As far as what to do, I would say anything that the mom would normally do would be a help. For example, if she usually made dinner, you could make a dish and bring it over.