All families have their own kind of drama. Remember that you can’t change anyone except yourself. As much as you might want your uncle to not be such a jerk or your mom to stop being passive aggressive, you’ll be more at peace if you let go of needing them to change. Sure, you can set healthy boundaries and speak your truth: “Uncle Joe, when you make racist comments, I feel really sad and angry, and it makes me want to not be around you.” If you’re gathering in your home, ask him to leave if he doesn’t respect that. If you’re the guest, take some time and space to yourself.
Try not to play into the passive aggressive behavior—just do what you need to do to take care of yourself. And good luck!