Dressed as a Sick and Abandoned Son, I Relied on the Imperial Examination to Destroy the Clan

See how a sickly young boy who was judged not to live to be twenty years old reunited his disheartened grandfather and his parents who were overwhelmed by the past in a run-down branch that was systematically sucked by his master's family, and used a pair of hands that could change everything to create a bloody path for himself and his family. PS: There is a female protagonist who appears late!