Yes, the students will still have access to Khan Academy but you will no longer be their coach nor see their progress.

OHT Archiving Classes or Deleting? As Christine says, even if you delete a class, your students will still have access to their Khan Academy account. You are no longer their coach or teacher, so you cannot see their progress. If you delete a class, you will loose access to their previous progress. If you archive the class, you can go back and look. For myself, once grades are transcribed to our schools LMS (learning management system ....online gradebook). I don't see any reason to keep access to my old classes so I delete most of them. Also I recycle names (Ex. Abbott Mod 1 Math 8) from one year to the next. I do keep one class from the previous year "open" but renamed, so I can show colleagues how to access student progress reports.

How do you archive...I see the delete button in the class settings window

From the roster you may select the button on the right hand side and under actions you can select stop coaching. This is not technically an archive because you will no longer have access to those students' progress.