We need to understand what OP would like to achieve. Although a seasonal hold is possible, it is not intended for durations shorter than 30 days. Reporting a phone lost or stolen could create a blacklisted IMEI nightmare (unless @Chad Burr has experience with this option and can confirm that it wouldn't be an issue).
Is the service the issue, or access to the device? If the access to the device is the issue, then I agree with @Greg Layton. If the service is the issue, then removing the sim card will do the trick, as per @Robert's suggestion.
Is OP's son under punishment? Going on a trip to the US or elsewhere? Incurring overage charges? Using their phone to spy on neighbours or for cyberbullying? Is a victim of cyberbullying?
I feel we know too little information.