I'm not aware of them allowing any openly incestual games. There are games out there that have stripped all incest references from their games, but then there are mysterious patches or hacks out there to unlock or restore the incestual content. I don't think Patreon so much allows that, as they either don't know about it, or more likely, they're turning a blind eye to it. I don't know if that's going to continue. I suspect there's a good chance they'll just keep getting more strict as time goes on.
DS chose not to go the patch route. I don't think the patch route can necessarily be trusted, as I just mentioned. I also don't think DS really wanted to continue with Big Brother because they're not an incest fan themselves. At the same time, I think they're slowing discovering that this Glamour game isn't going to be anywhere near as popular as Big Brother was. I suspect that DS will return to Big Brother in the future if a viable way of doing so on Patreon or elsewhere can be found without the threat of having the rug pulled out from under him. At the same time, I don't know how much life Big Brother has left in it. I miss the game, but mainly because the Lisa thing was left unresolved. Give me closure with her in one update, and I'm good. But if DS rebooted the game, or started a new incest one, I think that could be interesting. At least if he learns from the mistakes of this game. Of course, what I consider a mistake might be someone's idea of a highlight of the game, so there's no pleasing everyone.