Yes, the GAD possibility has been eliminated. I never questioned that he knew right from wrong. He was riddled with fear compounded by his disability. Father was into guns, mother kept one under her pillow, an alcoholic. They divorced. What effect did all that have on him?
Will anyone ever know what actually happened besides Nel's invented reconstruction? Can we imagine his summing up and Oscar trying to hold his ears? Here people seem to draw parallels to the Simpson case. That makes me crazy.