Are you sure you want to delete content based on the value in the check box? This doesn't allow for the user to change their mind or recover if they made an incorrect selection.
I would recommend you hide content rather than delete it. This gives you a more graceful method to re-instate content if the user changes their mind.
Also, your logic of Checked = Delete seems counter-intuitive. Wouldn't checked mean you want that content and unchecked mean remove it?
To demonstrate how I would approach this, add a tag value on a parent checkbox (eg aaa) and then select the children rows below that parent and add a bookmark using the same tagname. Note that the tag value must be a valid bookmark name.
Then run this macro
Code:
Sub ShowHideSubRows()
Dim aCC As ContentControl
For Each aCC In ActiveDocument.Range.ContentControls
If ActiveDocument.Bookmarks.Exists(aCC.Tag) Then
ActiveDocument.Bookmarks(aCC.Tag).Range.Font.Hidden = Not aCC.Checked
End If
Next aCC
End Sub
If your display options are not showing hidden text then this will allow the toggling of the children rows based on the checkbox value of the parent(s).