|Sounds like she needs install a Parental Control software, like Netnanny, Guardian,etc. Maybe this site is a place to start for reviews. I've used some free keystroke loggers that are just ok, and also tried the Guardian. It logs web sites, some keystrokes, but the paid version can run totally hidden so he'll never know it's there.
There is some free stuff out there, but they usually leave an icon in the tray, or something like that so it's not completely hidden. If he's not too PC savvy then that may work fine.