Disabled iphone!!!

You have two problems.

The most critical is that your son needs to recover the iCloud account the device is locked to.

Start at https://iforgot.apple.com

Once you have that straightened out, you'll need to restore the device: If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled

i know that you need to turn off the iphone and conect it with your computer. Then, turn off pushing the "home" and "turn on" botom while a design of itunes appear. For that, if you had pc with windows you need to had installed the itunes but if you use mac, don't need to install nothing. Later, open "itunes" with your iphone conected and there could appear your apple id that you was using before. So, when you have your apple id, try to recover it on the apple webpage. Also, if you can't enter to your iphone, you need to restart it from zero. I did it when it happened me