Complex sentence: He was told to write down the names of his close relatives so that they could leave the country with him and, realising that he would be unlikely to see them again otherwise, listed his wife, children, mother and niece.
Split into simpler sentences: He was told to write down the names of his close relatives so that they could leave the country with him. Realizing that he would be unlikely to see them again otherwise, he listed his wife, children, mother and niece.