I'm so sorry to hear that. This is a very hard problem for me because I have family I adore who are faithful members, and dear Mormon friends who are on Cake.
I helped my daughter move into her new house with a half dozen volunteers from her local ward and the vibe was so wonderful. Everyone was helpful, warm, fun, bound by a common interest in a really strong community, good with the children, etc. I had an overwhelming feeling of the good the church can bring and how I miss it.
Here's an example of my dilemma: our Stake President and Bishop came to visit me when I left, saying they really should hear why I'm no longer active. They're both wonderful people, decades-long friends, smart, accomplished, great families. I don't want to do anything to hurt their faith, which is so important to them. They genuinely love the church and can't imagine life without it.
But they wanted to know. So I gave examples like this one: The Book of Mormon makes it clear that vast populations of the Americas were descended from a Jewish family who sailed here from Jerusalem. We've sent out legions of missionaries to Native Americans and the people of Central and South America to tell this story.
But now we know there are no Native Americans, Aztecs, Mayans, Olmecs, or any other native American population with Middle Eastern DNA; they're all of Asian descent. I can't feel good about encouraging missionaries to teach Native Americans a false origin story about their ancestors. It doesn't seem fair that I should be suspected of wanting to sin or to be unfaithful because of that.
My two visitors didn't have an answer to that but we remain friends and they remain active in the church. I don't know how they process it except to say you can't believe everything you read on the Internet.
That's something I love about science: if you can find an error in a theory and discover a new one that proves to be more correct, you get a medal. My friend Simon Southerton, a former Bishop in the church and Phd geneticists who was the first to publish about the DNA of Native Americans, got excommunicated. His 6 sisters apparently are like your family, wondering how to think about him now. But of course his science has been validated tens of thousands of times by Ancestry.com, where anyone can get a DNA test for less than $100. And yet...