I was thinking literal nightmares & didn't read this thread till just now. Sorry about that!
I've gone through something similar. The perpetrator was a cousin who happens to be a son of the family matriarch. She's dead, but he lives in the house that became the family gathering place so.... Anyway, for years I've skipped weddings and funerals and reunions I'd have liked to have gone to because of him. And then came my dad's funeral. He'd asked me to speak so it was kind of hard to skip. I was desperate enough to tell a couple people what was going on and something kind of wonderful happened. They were going to have the family wait together in a small room and enter the church as a group. No WAY was I up for being in a small room with a crowd that included HIM. So I explained the situation to the minister (who I had never met previously). He was amazing. Said, "I would imagine you could use some privacy to prepare for your speech, why don't you wait in my office?" I had said something, I guess, to my step-kids. (Technically they are my EX-step-kids because their father & I are divorced, but I never divorced THEM.) Anyway, 2 of them showed up, unannounced, and waited with me in the office and walked in with me too. That cousin stared daggers at me while I spoke, or it seemed like it anyway, but he avoided me during the lunch afterwards.
A couple years later, I told a few of my cousins about the situation. It was wedding, funerals, etc that concerned them that I'd been skipping and I really didn't want them thinking it was because I didn't care. I'm glad I told them. They all handled it differently, but I'm sure they believed me. One in particular was pretty angry on my behalf, without asking a single question. It was a good visit and for the first time, maybe ever, I felt like I belonged to the family. I wish I could say it was smooth sailing after that. Well, no, I guess I wish I could say they set it up so I could be included in stuff after that. That's not the way it worked out. They all live a long ways from me and the family has the traditions that it does. I'm not going to events where I know I'll have to be around the perp so I'm not going to a family reunion at his house. A couple years ago, I suggested that I could come over, skip the reunion, but meet them all for breakfast the next morning & they couldn't promise he wouldn't come too. I'm sorry that that's the way things are, but I'm really glad I told them.
You don't owe anyone explanations and you don't have to tell anyone you don't want to tell, but good can come from telling the right people. None off this is fair. It particularly bugs me that I'm not the one who did anything wrong but I seem to be the one who keeps having to pay a price. It is what it is. But I'd suggest you consider confiding in a few select family members. Like maybe your nephew?