Dealing with Complex PTSD

You lived in a constant state of trauma with moments of standout events like your brother. It's definitely part of it and I promise you'll be able to process and move past it. Have you tried EMDR? It's been very helpful for me.

Yes. People can often be triggered by childhood experiences they had no control over, where they or someone they love were unsafe. It sounds like your dad parentified you, that he told you things a child didn't know how to process. CPTSD can cause distress about interpersonal relationships, so being sad about not having the type of relationship you want with your parent makes a lot of sense