Unlocking an old phone

My buddy has a Pixel 7 locked to Xfinity he'd like to pass to his mother. He has moved to another state and doesn't have Xfinity anymore. Is there a chance to unlock this phone, or is it a dumpster candidate?
He said he tried calling Xfinity, but the customer service drone kept asking him about his account number, and when he found his old one, he didn't know what to do with it.
The phone is paid off and should be unlockable.