For people asking, The rough motivations of the villain of this story can be roughly ascribed to two seemingly tied goals:
A) The desire to continue his legacy.
B) The desire to reconnect with lost family.
Now, Hunter is a Misogynist, like the whole thing is that he's an allegory and caricature for the sort of underlining themes house incest games tend to have, so of course he's not getting any of the women in his family to continue his legacy. This includes Drew, hence all the "I have no son any more/My son is dead" foreshadowing we were getting before Drew showed up, because I guess Hunter is one of those "Trans Inclusive Radical Misogynist" guy, so Sterling, the only remaining male in his line, was the next best thing to shape into a potential heir.
This stops of course the second Sterling's luck causes Hunter to get progressively more and more hurt, but we can see in the early moments of the game how Hunter was seemingly trying to get a student in him by nudging him in the right direction, and we can see that take form with Sean, who is canon to the setting as we all know just as much as best girl Nnena, in What If 7.
Hunter is also a predator with a deeply fucked up sense of morality, so to speak, meaning his desire to reconnect with his lost family now that he's so close at getting his dead wife back would be to mind break and fuck them into becoming, again Misogynist and again House Game Theme Allegory, his stay at home barefoot brood mares for him to impregnate non-stop, regardless of their dreams or desires prior to that.
So to keep it brief, TL,DR:
Hunter wanted someone to continue his legacy, thought Sterling could be persuaded to do it, but has now changed idea and is actively trying to outright kill him (And Sophia and Drew if we assume the reason why they aren't in the deaf and blind and in the forcefem endings is due to Hunter killing them, two other members of his family) due to his continuous resistance and a desperate desire to achieve his "golden" ending.
It's not that hard to follow honestly.
EDIT: Side note, it is to assume the next plan is to start grooming his clone into becoming his potential successor if the body snatching thing is but a red herring, just like communism.