There are several different populations to take into consideration when addressing death in a school. Addressing the staff, students, parents, and teachers is important and requires different approaches for each group. For help discussing death with these populations, visit these pages:
https://www.dougy.org/grief-resources/death-impacts-your-school/
http://www.griefspeaks.com/id97.html
http://blog.brookespublishing.com/supporting-grieving-students-what-to-say-what-not-to-say/