PLEASE HELP!

Hello iOS users, I desperately need your help. My son has an iPhone 5 and last night, he attempted to download the newly released jailbreak. However, something is not right. He told me that after the jailbreak was completed, the phone restarted. When it got to a white screen with the black Apple logo, it just sat there. And sat there. And sat there. He can hold the power button and the home button to turn it off. But no matter which way he attempts to turn it on, he can never get past that screen. iTunes does not even recognize the device when I plugged the phone into any of our computers. Neither he nor I know what to do to solve this issue. Should I worry? Any and all help is much appreciated!

I'm on AT&T's network if that makes a difference.