Teachers need to work with parents, particularly emotional ones, but principals and school administrators both set the tone for those interactions, and support (or don't support) their teacher in dealing with emotional situations.
In this excerpt from Building Bridges Between Home And School, you'll find a number of tactics school administrators can do to help teacher with those difficult situations. Includes a checklist that summarizes the things supportive principals "should" or could do.
Free to distribute, and copy. If you are a principal, a must read, and if you are a teacher who perhaps needs more help, drop and copy on your principal's desk (or not, use your judgment!)