Hi,

There is no way to directly add a co-teacher to a class, but there are two great workarounds for co-teaching a class explained in this article: https://support.khanacademy.org/hc/en-us/articles/203610350-Can-a-user-have-multiple-coaches-Is-there-a-way-to-add-a-co-teacher-

Directions for sharing Khan Academy content to Google Classroom can be found in this article: https://support.khanacademy.org/hc/en-us/articles/115000170227-How-can-I-share-Khan-Academy-content-to-my-classes-on-Google-Classroom-

There are also buttons to share content via Facebook, Twitter, or email next to the one for Google Classroom.

I hope this helps!