Max book pro requires four digit code to login

my friends mac book pro won't let him login.

instead of asking him for a password, it asks for a four digit code.

theres a ”apple.help@gmx.com” link below the code entry form to contact.

is this ransom ware?

he tried booting using cmd+R while powering up, but an image of a padlock

and the four digit code entry form appeared instead of a login screen.

what should he do?

thanks!