Wow, that’s a hell of a story; I’m sorry. Since you’re in a moment of realization: the word for what your aunt did is “gaslighting,” and it can cause lasting trauma. You’re right that, like other forms of abuse, when done as a child it makes one more susceptible to it as an adult.
Gaslighting refers very specifically to presenting a false narrative to cause someone to doubt their perception. His aunt didn't try to make him doubt his own senses, she was just lying.
