The real lust interest in this game is the neighbor. The mom and sister have simply been targets of opportunity, not people he has actively pursued. The "voyeurism" has been a matter of two occasions (at most), and you had to choose to pay attention to them. I want to say the dad got "sloppy seconds" on both occasions, but it's been months since that first time.
And I have some difficulty with your description of the MC. He's using hypnosis, alcohol, and drugs to get the neighbor allow him to get further and further with her sexually. Functionally, it's mind control/rape. I can't even say that it's necessarily letting a repressed side of the neighbor come out. He is using the hypnosis to try to erase the most obvious negative effects of the alcohol (i.e., hangovers), but that's more about covering his tracks than anything else. He certainly acts like a psychopath as far as I can see. No concerns over the impact of making the neighbor drink heavily, and surreptitiously giving her drugs, no sense of remorse or feeling that what he's doing is wrong: only the drive to get what he wants, by whatever means available. The only nod to what he's doing being wrong is the fact that he's trying to avoid being found out, and one gets the feeling that is entirely about not blowing up his own life, and not at all about the impact to others.
I'd say the words the previous poster used to describe the MC (pathetic, pussy, sissy) focus on his relative lack of interest in actively pursuing incestuous relationships, and in not being more immediately aggressive with his actual target. They completely fail to describe his utter lack of regard for the safety of others, or their feelings about, well, anything. Plenty of reasons to not like the MC or to feel uncomfortable with the story, just not necessarily the ones the previous poster saw (unless, of course, you're coming in with the same basic interests as him; his viewpoint is valid then. I'm just trying to look from a different angle).
