Do I help my best friend and her racist fiancé with her wedding?

So my Best Friend is getting married and she wants me to help her be their wedding planner because she doesn’t want to get a wedding planner and I’ve done it before with other friends and family the only thing is... I hate her fiancé. He’s extremely racist towards me and anyone who isn’t white. He has literally made me cry bc of the things he’s said. He has said before that if you’re not white then you need to go back to your country(I’m a second gen American but “I don’t look like it”). That’s just the tip of the iceberg! Sometimes he won’t let her see me because he’s insanely possessive and controls her life🙄 He’s also extremely sexist and has told me that women need to stay home and make and raise babies. He’s honestly full on corrupted her and everything she believes in but she’s scared to argue back because she loves him so much and doesn’t want to harm their relationship. With that being said... she’s still an important part of my life and was they’re for me through a lot and I just don’t know sometimes if I can help her with the wedding because her fiancé has been a nightmare from day one and Idk if I can take anymore of him.