Keyloggers can help you know what your kid is doing behind your back when you are not around... : https://www.geckoandfly.com/17868/best-free-keylogger-for-windows-mac-android-ios-to-monitor-your-kids-facebook/
This one seems easy to use... : https://kidlogger.net/
I know there are many mothers on Ovarit who may find this useful!
Hate to say it, but my first thought is that a child could also put one of these on their parent's computer.