Apple macbook pro running in circles

[Sangoma]

I just took over a macbook pro from my son, and he tried to reset it.

Now it keeps asking for a password to unlock the disk, the password is entered which it accepts as being correct, seems to restart, then does the same thing again.

tries a few time, got to different screens that ask the same thing, but it just loops through the same process.

 

[Nikon f1.8]

It needs to be removed from his Apple ID account, brother had the same problem with his when he tried to sell it.
Once removed you can setup as a fresh macbook