My sisters boyfriend is turning my sister into like a person who hates everybody..what do i do to fix this?

what i mean is my sister has a boyfriend who is racist and hates like different religions and people who are gay and stuff like that. well im the complete opposite and so was my sister ,until they started dating ,now shes acting all ignorant towards people and my friends what do i do ? do i just do nothing?? they've been dating for now almost a year?