You may want to look into Wavesecure, below.
It looks like it has the features you're looking for, and also comes with a secondary uninstall protection app, so there is less chance of your son removing it. Though I haven't had to use all of the features (thankfully), what I have used works nicely.
While you can password protect entry to the application on the device, the downside is that if he gets curious and decides to Google it, he will likely be on to what you're doing...unless someone can chime in with a method for hiding apps from the tray/market, etc.
The other downside is that they now charge a subscription fee $20/yr.