Complex sentence: His father is the son of Greek immigrants, Heracles Sedaris and Adamandia Thomakou while his mother, who has roots in the United States going back to Colonial America, is of English ancestry.
Split into simpler sentences: His father is the son of Greek immigrants, Heracles Sedaris and Adamandia Thomakou. His mother, who has roots in the United States going back to Colonial America, is of English ancestry.