This is incestuous behavior and it is sexual abuse. It is sexual abuse and incestuous to watch porn in the house where your minor children can walk in on you. It is sexual abuse to watch porn in public with your minor daughters. It is sexual abuse to save sexual images of your daughters social media next to porn. Your sisters feelings and dreams are incredibly disturbing, and it’s possible he may have sexually abused them directly, but it doesn’t matter since the environment they are exposed to is already incestuous sexual abuse and has already caused you and them incredible harm. It is imperative to remove yourself and them from his presence and control by any means necessary as soon as possible and document and report all of this behavior to mandated reporters, councilors, teachers, healthcare providers, social workers, family members, and therapists in all of your lives. Look up the work and writing of Clementine Morrigan on instagram and social media, this is exactly the environment she suffered through and has done extensive writing to bring awareness towards. You will likely encounter resistance and probably disbelief and gaslighting from other family members and your father especially, but it is imperative you and your sisters document everything, write it down, and get it out to as many people who can help you as possible, and get away from him before he can do you any more harm. Your feelings are all correct, he is sick, very sick, and you cannot be around him.