How to allow a keylogger to monitor children's activity

I was using the Spyrix keylogger child monitor to keep an eye on the activity on my son’s computer. We have had issues with him in the past.

However, with the last update from windows a couple of days ago, every time the computer loads the keylogger, Avast quarantines it thinking it is a virus. I had to completely uninstall it. I tried reinstalling it, but could not get it to work at all.

How do I get Avast to leave this keylogger alone? I know normally they are bad things, but this one worked very well for me to keep an eye on my son’s computer and internet activity.

https://support.avast.com/article/168/ (Excluding files/websites)