i think the niece had been doing it from the start and the uncle doesn't know that it's real bc the niece act like it never happened when morning came. That night, the uncle didn't drink the alcohol (he throw it on the sink) to catch the niece but the niece is still trying to gaslight him into thinking that it's just a dream. So since he's disgusting, he let himself do it eventhough he knows that it's real and just keep telling himself that it's a dream to convinced himself that what they're doing is okay.
i think the niece had been doing it from the start and the uncle doesn't know that it's real bc the niece act like it never happened when morning came. That night, the uncle didn't drink the alcohol (he throw it on the sink) to catch the niece but the niece is still trying to gaslight him into thinking that it's just a dream. So since he's disgusting, he let himself do it eventhough he knows that it's real and just keep telling himself that it's a dream to convinced himself that what they're doing is okay.