When Chen Shi died, he was only nine years old, and at that time he was merely in the Divine Embryo Realm, at most the Golden Core Realm. After his death, his soul couldn't take any mana with it and entered the underworld alone, surviving was already very difficult, let alone cultivation?
Moreover, without a physical body, how could one cultivate?
Without a physical body, there is no way to refine a Golden Core, Nascent Soul, or Primordial Spirit, no way to establish a Daoist Field, achieve Unification, or cut the Three Corpses.
As for cultivating to the God Refining Realm, it's simply impossible!
Chen Shi suddenly said, "Perhaps then I attached myself to a skeleton or some other shell, cultivating within a false body. There are many pre-Qin cultivation techniques scattered throughout the underworld, legacies from the Great Shang Era, and I might have acquired a technique similar to the Blood Lake Scripture, which made my cultivation speed extremely rapid."