Perhaps even throughout the entire Wizarding World, only The-Boy-Who-Lived, who had once obtained Snape's student-era textbooks, inherited a fraction of his legacy. This was also why Snape tacitly allowed Draco to protect that Boy-Who-Lived.
Snape's research and creations were lost! The legacy of a young Potions Master in his late thirties had been lost!
Lord Voldemort knew very well that Snape was dead; he simply refused to admit it to himself, even though everyone else was certain Snape was gone.
Chapter 237