The Castaway Returns to Reckon

Lu Yuan went missing as a small child and was raised by an adoptive father. At fourteen the Lu family found him and brought him home. Another Lu Yuan was waiting there, the boy they had adopted in his place, who made his life difficult in ways the parents read as the returned son being the problem. Before the college entrance exam he was diagnosed with liver failure. He died at home, alone, while the Lu family were away on a trip and knew nothing about it. His body sat unclaimed. He comes back as Qin Zhaoyang, a different name and a different standing, and takes apart the fact that Lu Yuan had been living under a stolen identity. He gets what he is owed out of them, and he cuts the Lu family off.