I thought the nephew turning up was another way of showing how families can re-unite.
The uncle Clive used to send nephew Jerome, I think his name was, Christmas cards, he obviously felt so guilty he had never looked for his brother Matthew when he was chased that night, he never went to help him.
The nephew had a poor relationship with his dad, and after Cassie/Sunny interviewed him after his body was found, think it made him re think about his estranged family. He had a wife, baby and steady job, so had made a better life for himself despite a rough start.
On another note, we never saw any more of Sheila Hancock’s harridan of a mother!