The conversation between human and AI assistant.
Why was Harry not able to see Thestrals even when he was leaving for Privet Drive at the end of fourth year even though he had seen Cedric die?
Do all wizards see Thestrals after they witness a death?
Not necessarily. Wizards and witches have to fully comprehend and accept the reality and finality of death before they can see Thestrals. It's not just witnessing death that allows one to see them.