The co teacher can simply duplicate a class that includes the students whose progress she needs to track. 

To duplicate an existing class from another teacher in your school follow these directions:

-From your Teacher homepage, click on Classes. 

-On the bottom left of the page is a link that says "Duplicate Existing Class." Click on the link and then use the dropdown menu to choose the teacher's class you would like to duplicate. 

-Choose the class name you would like to duplicate. 

-Once completed, the class name (with the same students) will appear on your own class list.

To monitor students in any class, follow these directions:

-Click on the blue link with the class name.

-Choose the second tab, which says Sessions & Reports. 

-*Make sure to choose the correct Course name from the dropdown menu.*  

-Now you can monitor the assignments each student in the class has completed in the Course you chose at the top.

This is the easiest way for the co. teacher to track the student's progress.