The Instructor Role is defaulted to restrict Instructors to only see classes that they are scheduled to lead. If you want all Instructors to see all classes, go to Admin > People > Roles > Edit next to the Instructor Role. In the Instructor Role, turn 'Use For Instructors' to Off. This will apply to all Instructors.

If you only want one Instructor to see all classes in the Booker, we recommend making a Role with the same permissions as the Instructor. Then, applying this role to the user and removing the Tie to Instructor option on their Profile.