Yes. The function will send the Sunday email to all parents who have an event in the next two weeks. So if you only enter an event for the 6th grade, only parents of the 6th grade will get the weekly reminder. However, if you enter an event for the whole school, all parents will get the weekly reminder.
The weekly reminder will gather all of the events that are related to a particular family and include them in a single weekly email.
Each event includes its date and time, a link to add it to Outlook, and notice if there are any volunteer opportunities associated with it.