The film in question is called The Strange Thing About the Johnsons which is about an African American middle class family. You have Sidney, the renowned poet, his wife Joan, and his son Isaiah who...has an obsession with his father.
In short, the film is about the domestic abuse that happens behind closed doors, but in an inversion, the son is the perpetrator. Isaiah was really a sociopath who sexually abused Sidney for 14 years, rendering him a psychological mess. As for Joan during all of this...she knew. But she wanted to preserve the image of a perfect family.
Isaiah is a charismatic young man who puts on a front of politeness in public and is successful. However, he is actually obsessed with his father to the point that he gets envious of the affection Sidney has with his mother. He is possessive, but also greatly narcissistic, always taking advantage of his father, and it is shown pretty well that Isaiah does realize what he's doing to his dad is wrong, but he keeps Sidney in the abusive relationship through victim blaming. He speaks horribly to him, accuses him of starting the abuse and ruining his life, and threatening him with physical harm if he were to publish his memoir about his years of abuse. Even when Sidney died, it is made abundantly clear that Isaiah viewed his father as an object he could exert his force onto, and overall treats Sidney's death the same way a kid would when their prized toy is broken. Prior to Sidney's accidental death, Isaiah breaks him through a Hannibal Lecture as a means of keeping his father in the abuse and once again shows that in the end, he cares more for his public image being ruined than the fact that he brought his father to that point.
Isaiah eventually grows up and gets married. But the abuse persists. Sidney takes it upon himself to write a memoir as a compilation detailing all of the awful things Isaiah had done to him. Isaiah discovers the manuscript, and threatens harm to his father if he published it.
MORAL EVENT HORIZON
At a New Year's Eve party, Isaiah deliberately breaks a glass as an excuse to stay behind. Upon finding that the door to the bathroom was locked, he kicks the door off its hinges and viciously assaults a horrified Sidney. While we don't actually see it, it is blatantly obvious what happened. Sidney secretly retrieves a second copy of his manuscript and as he was leaving with it, Isaiah catches him and accuses him of starting the abuse and tries to guilt trip him. Sidney runs out of the house...only to be killed by a speeding van. Isaiah seemingly breaks down over this, and afterwards came the funeral.
Joan confronts her son, inquiring him on when the abuse started. This then segues into a brawl ending with Joan killing Isaiah with a fire iron.
So...okay. Isaiah has heinousness down pat due to the pattern of committing these acts for 14 years, and aside from that, he has attempted murder under his sleeve as well. With the actual rape and sexual abuse, it is actually played pretty seriously all things considered. The film has its moments of Narm, but for the most part, it is played as a thriller.
Has no resources he can exploit, but makes up for it by being as terrible as he could be.
For a Freudian Excuse...Isaiah claims his father started the abuse, but we are given no indication of it aside from Isaiah misinterpreting one of his acts. So, it looks more like Isaiah is trying to deflect blame.
Mitigating factors...well, he was insanely jealous of his mother, and had no qualms with trying to kill her. So...yeah. As for his wife, while he is shown kissing her at a party, he turns his attention towards his father. He later breaks a glass and lies about staying behind to help clean. As such, he is more indifferent towards her.
With Sidney. It's more complicated. He professes to loving him and seems truly sorrowful over his passing. But...is this really because he genuinely cared for him, or was he upset he lost a possession. Any other scene involving the two sees Isaiah as being possessive of him; he has no qualms with threatening physical harm towards him because he was concerned that the memoir would jeopardize his own life and reputation rather than because he felt guilty about it. He back mouths his father any chance he got, and ultimately forces him to believe that everything was his own fault. Even with the death, Isaiah never once acknowledges it was his fault over what happened to Sidney. With the continual abuse and manipulation, I lean towards him viewing Sidney as nothing more than his possession.
Overall, Isaiah is actually a rather realistic take on a domestic abuser which was why I initially hesitated. The film delves into how households like these exist, but otherwise, no one speaks up about it due to fear.