I mean Poland is in European Union so this should not be happening here or at least there should be a way to find an adequate solution.
In all countries in the EU there are minorities who believe they get a bad deal. If you talk to any member of a minority group in Poland they will inform you things are greatly improving.
As per your request there's an organisation based in Warsaw called nigdywiecej.org they specialize in racism your friend should contact them and discuss his situation. The smart money would be on your friend transferring to another Polish university, offering the same course. You will not beat or change the system in Poland crying discrimination.