Childhood memory repression
I have a character who is involved with some form of childhood trauma (it's never specifically named in the book as his adoptive parents find him wandering the streets after it's happened) around the age of six or so. When his adoptive parents find him he is alone, covered in soot as if he had escaped from a fire of some kind (it is in the middle of a war, though, so this is not particularly abnormal), and cannot/will not speak. They take him home and take care of him.
Some couple weeks later he finally begins to speak, warming up, but they find that he has no memory of anything before they found him (well, perhaps wandering the street, but not of the traumatic experience). The bit of a twist is that the little boy, even though he can't remember anything before, has an eidetic memory and sometimes catches glimpses of those repressed memories through dreams.
So, this is my question to anyone who has any medical and or psychological knowledge: Is this possible for someone with such a gift as an eidetic memory to completely wipe out the earliest years of their life due to trauma?
If more details are needed, let me know.