Most of the avns I follow the mc is the father. But the ones I can think of the top of my head are Ripples(it uses honey select models), Bad Memories, Twisted memories (also uses honey select models), apocalypse( this is more of a sci-fi/fantasy game and it can get pretty dark depending on your choices), Dreams of desire, Sisterly lust, apartment 69 and Life in santa county (it gets updated like once a year now). There are probably more that I've played but those are the ones I can think of right now. For most games where the father is dead, it doesn't seem like it is a big part of the story. I think in most cases devs just don't want the players to bitch about NTR. I've seen people complaining about it when the mom is supposed to be a love interest and the father is still alive and they are still married. For incest games the common tropes seem to either be, the dad is dead at the start of the game or if he is alive he is a massive asshole and hasn't had sex with his wife in years and that ends up being one of the reasons why the son is able to seduce her.