In Front page settings do the following:
Before login : Do not show List of courses or List of Categories, only show announcements and News items
After login: Show only Enrolled courses, do not show list of courses or list of categories.
Now you have to do some changes in code too to hide the "All courses" link which enable when you set the front page to show only enrolled courses.
You can hide this link in renderer.php file which you will find under Moodle>course>renderer.php
In the file search for "All courses" then comment out these two lines:
//'viewmoreurl' => new moodle_url('/course/index.php'),
//'viewmoretext' => new lang_string('fulllistofcourses')
After doing this the parents when logged in then they can be able to view their course in which they are enrolled.
Hope that help.