Q: I phone app

What do you mean the user name has been disconnected? Apple IDs do not expire nor can they be disconnected in any way. The associated E-mail account may be non functional, but the Apple ID continues to exist and work. 

If this is an iPhone 3G or 3Gs, (Identify your iPhone model - Apple Support) you can try to Restore it through iTunes, but this will wipe any and all data from it.

Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings - Apple Support

Beyond that, you could attempt to recover his Apple ID and password through http://iforgot.apple.com

Otherwise, you may need to contact Apple Support and have them directly help you with the account.

https://www.apple.com/lae/support/itunes/contact.html