I thought this also at first but having reread this a couple times I’ve come to understand that it’s not entirely pointless but to show the dads mental state and obsession with his wife as it extends to his son as he sees her in him or sees him as an extension of her. It’s fcked but it’s psychological I guess lol
I am rereading it after a long time, I thought like you at first too. But now it makes sense cuz the father himself wasn't in a good state, he's mentally ill. That prostitute who was killed looked like his son and it was hinted too. This story is really not for the weak
the random fucking incest threw me for a loop also.. there was literally no reason for that, nothing to be gained story wise