That sounds like a form of depersonalisation, to be entirely honest, although using autosuggestion to create such a mental state, while it has a perverse logic to it, is still pretty out there.
I actually have a character in the thing I'm writing who creates a kind of second person in his head based on his dead, somewhat abusive older brother along these lines. Which is weird, because that was meant to be a part of that character's extreme alienation from social contact, which is clearly not the case with this dude.
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I am so very glad nobody was around with a formalism