3 percenter visiting nextdoor

I live right next door to my husband's Aunt and Uncle. We live in my husband's late grandparents house and share a driveway with them. The Aunt and Uncle are retired but sell wine from home so there is often vehicles parked in our shared driveway for short times.

Any way the other day a noticed a truck that is there on a fairly regular basis. This time as I

walking by I looked at the bumper stickers. One was a back the blue type sticker and one was a 3 percenter bumper sticker.

I texted a picture to his Aunt and asked about it. Sometimes like "how long is your client going to be there?"

She answers that it's their friend visiting and if the truck is in the way just ask him to move it.

I am a little in shock I didn't think they would be friends with someone who is in a white nationalist militia.

I asked if she know what the bumper sticker in the picture meant. She said yes they have been friends with him since long before he joined the 3 percenters.

I now feel very uncomfortable and really don't want kids going over to their house. I know we need to talk further but I honestly don't know how to approach the subject.

*I am adding this because it's relevant: I am white, the Aunt and Uncle are white, my husband is biracial identifies as black our kids look white.