The routes will eventually split apart as each character does things different. Son spied on mom and aunt in bush ? Father with daughter in cave. Different choices lead to different outcomes
Fallacy of comparison. Those routes are independent of each other, what I mentioned complemented each other. After the bath scene with Mom in the Son's Arc, he's supposed to talk with Dad about Karen. In Dad's Arc, Karen saw Son leaving the bathroom (I reckon this is the Rape scene) and hid behind the kitchen counter listening to Son-Dad's conversation about her. This is where Karen snuck up on Dad.
This is where it gets confusing. In Dad's arc, the son is sleeping adjacent to the couch where Karen is molesting Dad. In the Son's arc, Son
SAW Karen on top of Dad. The story shouldn't have different outcomes, it's supposed to complement all routes. What the fuck?
Even if we assumed parallel routes, the inconsistency remains. The split-outcome depended on the son's choice of either waking Dad up or not. Apparently, in Dad's true arc, son refused to wake him up; which Aunt sent him to the bathroom. Remember, even if the rape scene happened or not, there's no excuse for the Aunt not being present on where Mom HEARD the commotion right after Aunt sent Karen in her room. In Son's arc, after Aunt sent Karen in her room, she went to the bathroom.
That bathroom scene with Son + Aunt happened earlier in the Dad's arc. Son got out of the bathroom which prompted Karen to hide behind the kitchen counter; before she molested dad.
EDIT: Ok, I've replayed everything three times. Son is actually sleeping adjacent to Karen when the molesting happened. The consistency is fine, it's just way too confusing.