I would recommend Net Responsibility for this. I was the initial developer of it several years ago, though it's now been rewritten by the new maintainers and I don't know the details of how it works. But here's basically what it does:
- First, it monitors all the URLs requested at a low level (so that you can't get around it by switching browsers or using the private browsing mode.
- Then, it periodically sends reports to the accountability partner (in this case, you). I think that the way the reports work has been changed since I worked on it, so I no longer no too many details, but the reports do include a list of the websites visited.
- Finally, it includes in the reports whether it's been shut down manually (as an anti-circumvention measure). And, of course, if you don't get a report when scheduled, you'd know that it had been disabled.
I don't recommend using this software as a way to sneak around. Make it clear to him up front that the software is there and that if he tampers with it he'll lose his computer privileges.
Finally, if you want to prevent tampering, don't give him a full account on the machine. Either give him a non-administrator account, or configure
sudo to prevent access to Net Responsibility. The latter option isn't easy to implement, though.