I will start out by saying that I do not personally have a diagnosis of dissociation. Here is a hypothetical situation... The story includes some stuff about childhood abuse, and how 2 siblings react and cope in different ways. Please, only read if this does not sound triggering...

2 siblings grew up together in the same household and went through the same physical and emotional abuse, though one of those siblings had it worse. The sibling that had it worse somehow doesn't remember any of it, nor most of his/her childhood, and is doing mostly okay in adulthood. The other sibling remembers everything and is also doing mostly okay in adulthood, but not without sadness and grief from the past. The sibling that forgot everything is sad about not remembering their childhood and longs to remember, but the sibling that remembers thinks that the other sibling is better off not remembering because it was terrible and went on for over two years. The sibling that does not remember also has some anxiety in certain situations (a superior getting upset with them will make them shut down and cry). The other sibling has the same anxiety except theirs happens more often but is less extreme. The sibling that doesn't remember also has an ability to completely "zone out" in any situation if they so choose (ex: another person inflicts extreme pain, and the sibling that doesn't remember is able to act like the person inflicting the pain is doing no harm, thus making the person doing the harm confused and less inclined to continue). (Note: the last time that the sibling that doesn't remember used this ability in the past, they may have not been able to move a certain body part for a couple of days due to some damage that was done to it).

This is just a general description of the situation. My curiosity lies in how the sibling that doesn't remember got rid of the memories, and I am also curious in thoughts on which sibling developed a better coping mechanism.