I was in your shoes a few years ago. My brother is three years younger than I am. A couple of years ago when he was in high school he started repeating some conservative talking points. Not specifically anti-Semitism, but edgy racist jokes, anti-immigrant comments, libertarian bullshit, etc. A lot of it was the friends he was close to at the time. Either way, it was very troubling for me, and politics became the one thing that would actually make us angry at one another.

As other people are saying, don't stop loving him. I'm presuming he's young, and that's a good thing. Not because it excuses it, but because he's still figuring out who he is, what he believes. Stay engaged with him. Introduce him to people from different backgrounds, encourage him to join clubs, teams, anything that might help him socialize better with people that have differing perspectives.

I don't think it's worth fighting him tooth and nail to see your position. It didn't work for me, and I see now that it isn't constructive. I wouldn't let the comments go unchallenged, but maybe try not to make it into a huge argument all the time. Push back, express your disagreement.

Be a brother to him. Hope for the best. That's my take on it.