My best friend confided that she wants to die. What should I do?

Should I call someone, or would that be betrayal? She seems to be in a good marriage, but she hates being a mom and being married. My mom said I should tell her to have a short separation to see if that's really what's making her depressed. I'm afraid if she leaves, she won't have anything keeping her from doing something stupid. Please help. She's coming over soon.