What I think Chyos can do, to avoid risks with patreon is only one thing. If the player has the switch deactivated, the mother will not be the mother, but the classic mother's friend. Or a normal woman. With whom at the end to start something in a different way (Or it's simply dead and whoever has the switch deactivated therefore loses a possible additional relationship in the game. But I don't think so, because in that case some people would then complain about it). For those who have the switch active, instead the mother will still be the mother and therefore there will be an incestuous relationship.
I think the best choice for Chyos is to create two versions. A patreon and a Subscribestar. Where one has very specific content and the other enables content that patreon does not want. It shouldn't be that difficult for him or cause him any more commitments. Because in one he will not insert that particular context. While in the other he will have to insert it. For me this is the only real alternative. Because by doing so, he will bring new users to Subscribestar and will understand that that fetish brings a lot of extra earnings. Since in that way he can add more relatives in the game, without bothering anyone.