In my family, there is only one liberal. She knows from past experience to keep her mouth shut about politics during family gatherings. The only time she challenged the conservative viewpoint.....she was ganged up on...and it was verbally brutal. I broke it up by recommending that she come lurk on this site awhile and read a few books about the Clinton/Gore era....to educate herself.
Nice family...Thank God I am not part of it even though I would have been on the conservative side. I am glad that my family loves everyone regardless of differences of opinion. Hope you family comes to the realization that family is more important than politics even though your sibling was wrong to be liberal. LOL.