help me

Your friend should read the articles below

If you forgot your Apple ID password - Apple Support

If you forgot your Apple ID - Apple Support

What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support

See if he can recover the password. Enter the Apple (iCloud) ID and click Forgot Password.

Apple ID - Manage

Apple ID – Forgot Password

If necessary, if he is the original owner, have him take the device, the original purchase receipt with the serial number, and a photo ID to the nearest Apple Store.

Genius Bar Reservation US

or contact Apple ID Support. They will need to see the original purchase receipt/paperwork also.

Apple ID Support

Apple ID Support (2) 

Apple Support by e-mail or chat         

Apple Support using Twitter

Or fill out and submit this form.