Students do help each other out

You are working on the final assignment in the course.

A couple of days ago you shared your files within your study group, while discussing your assignments. Now you meet the group again to talk over the final details.

When reading the other group members’ projects, you find that your best friend in the group has copied a large part of your background section.

When you confront him, he says that you are allowed to use unpublished work. As it is only a page and from the background section, it would be OK. And anyway, all the other students are helping each other out by copying small amounts of text.

Whar do you do?