It's a real test of how real a friendship is. There are lots of people who enjoy spending time together, talking, laughing, remembering the good times, everything's great. But start to open up about some real trauma and you will drive 90% of them away.
They dont have tools, dont know what to do. But more importantly, someone who was in the same situation or did not studied it a lot is simply incapable to truly understand. They can nod, listen, validate, but wont be able to puzzle out half said things, badly expressed things. They won't be able to see logical consequences of what you talk about unless you point them out.
Meanwhile, someone with the same experience, even if not friend, will be able to understand much more and more easily.
It is not so much about some moral or relational failure on their side, it is simply that it is impossible to imagine feelings and situations you never had.
Varies by friend. Some are open to it, others not so much. In general I've found that talking about trauma with friends isn't very useful even if they are willing to engage.
