What should I do ?

I have a friend who I have known her for 6 years and she has been with her boyfriend for a year . He is always saying racist thing about her in front of me and I tell him to not say those things and I even tell her to tell him because it makes me feel uncomfortable and he doesn’t stop. She tells him but he doesn’t stop. She is a good person and good friend her boyfriend is the problem. He sent me this on Instagram and I just don’t know what to do I don’t want to loose her because of him but I feel like I will.