I don't think you'll find many, and I'll explain from the perspective of both a new game developer and a veteran porn author.
1. Ever noticed how in the media (movies, books, TV etc) families tend to be very small? Mostly only mother, father and 1-2 children. You'll almost never encounter larger families. Why? Focus.
The more characters you add, the more your reader/player/viewer has to remember. Another name, another face, another relation. So any character you add must be meaningful and the more characters you add the more focus you lose.
2. In porn, most characters will have one role: an object of desire. The rare ones who are not will represent a fetish or taboo or highlight the MCs personality in some way.
As you can see, the "good" father takes focus but unless he is an asshole or wimpy, he can't represent a fetish or taboo. A dead father is a great (if a little cliché) asset: he can introduce drama and mystery into the game, can explain in a way why a young MC acts more mature than his age and a lonely mother who needs comforting... well, you can never have too much of those, can you?
I've been writing porn for 25 years now: the father is always " 1) Dead (the most common), 2) An asshole, or 3) A wimp/sissy/simp/spineless ".
