How do I keep Avast Antivirus from deleting clevguard spy app from my husband’s phone?

Avast Antivirus may automatically delete applications from your devices. However, sometimes this may be false-positive alerts for secure applications.

Exclude the application by navigating to Avast’s Settings/ Active Protection/ File System Shield Settings/ Exclusions. This will exclude the app that keeps getting deleted by Avast. from a particular device.