Complex sentence: Still traumatized by the death of his parents and older brother in front of him when he was young he doesn't like to socialize with people and is nicknamed "Death Ray" by all his colleagues because of his stern blunt personality.
Split into simpler sentences: Still traumatized by the death of his parents and older brother in front of him when he was young. He doesn't like to socialize with people and is nicknamed "Death Ray" by all his colleagues because of his stern blunt personality.