Money on it now, ahyun's uncle is actually her dad. He shows alot of affection and concern for her throughout this arc. He spoils her lots, he's worried about making the wrong move that could put ahyun's life in jeopardy (remeber that hanging scene) , frequently tries to comfort and reassure ahyun during extra stressful events (caused by karma ofc , lol) and frequently involves ahyun (her safety, thoughts, etc) as a factor before making any moves. A BIL getting it with his SIL who has a kid likely wouldn't show this much consideration for a neice/nephew (and the toxic sides would disregard them entirely outside the mother's attention/view)
Money on it now, ahyun's uncle is actually her dad. He shows alot of affection and concern for her throughout this arc. He spoils her lots, he's worried about making the wrong move that could put ahyun's life in jeopardy (remeber that hanging scene) , frequently tries to comfort and reassure ahyun during extra stressful events (caused by karma ofc , lol) and frequently involves ahyun (her safety, thoughts, etc) as a factor before making any moves. A BIL getting it with his SIL who has a kid likely wouldn't show this much consideration for a neice/nephew (and the toxic sides would disregard them entirely outside the mother's attention/view)