unlock phone

My son bought a Galaxy A15 5G recently and put a lock on it using Google account.  He has a head injury and has forgot what his google password is.  How can he get past the login screen?  His google account only recognizes his old phone number and he can’t update to his new phone number.  Google wants to verify who he is with his old phone number.  He never set up a recovery phone number or a recovery email.