If you are uncomfortable about his actions you must tell him
There is not a way to monitor a app from a router. You can only monitor it from the computer.
monitor
monitor
tail -f /var/log/messages
Yes.
yes Laptop have monitor but people calling it a display or LCD
To view system messages when telnetting, you must enter the terminal monitor command.
You will need a few minutes with the device he is using in order to delete the app but then he will simply download another one and keep the device as faraway from you as possible.
Monitor
That's illegal !
Your business can read your instant messages if they have programs set in place to capture code words or screens. Some businesses do not monitor their employees that way and some do.
They don't read everything, but they monitor the internet, if that's what you mean.