Alert Preferences for Checklist/Task Notifications

A funeral director brought up that they receive email notifications when anyone edits or completes a task in a checklist. He is the owner of the task but does not want to receive email notifications of this. There is no current setting that we are aware of in Alert Preferences where they can choose how they want to receive this notification. If they could select whether they want it by email, text or turn this off, they would appreciate the control over how they receive the notifications.