Racism in school for my siblings

So all of my siblings are adopted out of DHS and are either black, half black or Mexican. Brother got called a n*gger today in school and it infuriated me. I delt with bullying in school at that exact same age but I never had to deal with racism so I don't even know what to tell them when it comes to advice on how to handle it. He's gone to the school counselor and it's happened twice now and she's like well if it happens again I'll deal with it! NO IT SHOULD HAVE BEEN DELT WITH IMMEDIATELY. What are your thoughts?