hello Abdulhadi. I tried on our School demo site https://school.moodledemo.net. There we have a role parent, which you can use by logging in with the username = parent and the password = moodle. This is Joyce and she is the mother of a boy and girl, Barbara and Charles whom you can see on her dashboard. She can access their profiles but when I tried your trick of changing the user ID this parent was not allowed to access any other profiles, so we need to confirm if it is your settings or the documentation which needs clarifiying. Can I ask if your parent is enrolled in any courses at all ?