Well said for the eldest child unrequited push to pursue "perfection" role while allowing the youngest to be a child. I don't believe that children innately create psychological damage in their siblings as much as they are promoted into picking up dysfunctional family patterns and characteristics are reinforced how all behaviors are, it's rewarded ( at least in context to being the outsider/ dissenter to the pattern). It's as if in order to justify/ normalize their own abuse experiences adult children of dysfunctional habits systematically shame or shun into conforming, as a ritual of honoring the legacy of the family heritage by passing it on.