If this is happening as a child who is there to trigger a memory or identity out so that what is being dissociated is told to an adult so that it stops? What is being taught to a child at that age? What if pain is dissociated? What if terminology a child uses doesn't get adults attention enough to investigate? I was told I better not say anything, what if the plan in my mind was to not say anything anyway....Who is to say I need his help to dissociate! I'm not sure why your comparing a sibling, but the bottom line is your sibling doesn't owe you anything. I tried to get something out of my sibling that would help me possible associate memories, it was the wrong thing to do basically I picked up a tactic a therapist showed me, well used people to show me that alter used....In fact, really none of my family members owe me anything no memories no triggers no nothing. At the same time, though, if carefully fully explained I would think well yes why wouldn't my sister not want to help me with memories so that the prognosis might be positive one. The only thing she can consciously say is I don't remember....I have to accept that!