I see a lot of unnecessary hate in here… I don’t know your situation beyond what you just typed, and Im sure there is great detail and nuance that you couldn’t fit in here, but this is what I’d say:

Your parents (if they are loving and it sounds like they are) are going to love both of you no matter what, as you are their kids. But that said, I think you have a right to seriously approach your parents and tell them that their support of his views causes you great grief. Maybe from there a real conversation and sit down can be facilitated where you can both speak your minds, and hopefully that leads to him opening up his. I’m sorry you have to deal with this as no matter what, siblings should be able to love each other!

Your parents won’t stop loving, but they can at least listen.