Seeking games about relatives/ step relatives forced sex and prostitution.

[cocopaaa]

desert stalker comes to mind

 

[Fairfield]

Restore Her Career is the standout example, where you corrupt your mother, though for now MC makes clear that he's not going to pimp her out. You can do that in The Tyrant, though.

 

[Freyr]

Free Cities with pregmod seems exactly what you are looking for.

It's mostly text-based though.

 

[Chase22Roge]

Maybe "My legacy" saddoggames ? there also forced corruption between relative

 

[Dafuking]

Personal Assistant: Blackheart Edition

 

[bomb john]

Bone tales: the Manor, but there is no prostitution.