Macbook locked...

[Saamukl]

Hey,

My brother have problem with his mac. You can see the picture of the screen.
What can he do?

 

[Fishrrman]

"My brother have problem with his mac. You can see the picture of the screen.
What can he do?"

Enter the required password and hit return.

 

[Weaselboy]

Hey,

My brother have problem with his mac. You can see the picture of the screen.
What can he do?

That is what is called a firmware password. If he does not recall the password he used to enable that feature, he will need to take the Mac to Apple along with proof of ownership, and they can unlock it for him.

https://support.apple.com/en-us/ht204455