NC as this is very outing.
My father left home when I was about 3 and my little sister was 1. I didn't see him even once until I was 16. He was, despite my mum keeping a somewhat positive tone around the subject of him growing up, a complete and utter arsehole. Luckily meeting him led to meeting my little step-sisters and my little half-brother, who even though my father has now left them, I am still in touch with today.
I also have a half-brother who is about three years older than me. My father left his mum when my brother wasn't even born yet, and his mum brought him up under the belief that someone else is his dad. He has finally been told the truth and sought out myself and my little sister, and has been told about our younger brother too. We've been chatting a fair bit and have a lot in common, but he hasn't yet brought up the topic of what joins us all genetically: our father.
I've been trying to prepare myself for what to do when he does bring him up and I'm at a loss. Obviously, he knows that my dad has routinely left his children, but the trauma he caused me at 16 is really, really awful, and I don't know if I should go into it or not when he does ask. My little sister hasn't seen him since she was 1 so I'm the one with the best idea of who he is, and I feel that carries a lot of weight.
So, do I go into detail about the ins and outs of it, or just say something like, 'We've not had the best relationship with him'? What would be easiest or most productive to know? I'm cautious that he may want to reach out to his father, and I feel like he should be prepared, but I'm also not sure what's right here.