NONE of these women are of relation, and subsequently will fill the part.
So, the part of the "Landlady" (TO ME) just screams "Stepmother". (IMO) No real mother would so blatantly point out the estranged relationship between her children.
That would also explain the comment made by the "Landlady" at breakfast. You just need to find a "Guardian" of sorts that is or possibly is sleeping with Dad, and that has played some authoritative role in the life of the main character and his siblings. However, there ARE alternatives that I can see that SHOULD appease the gods(Patreon), yet at the same time SHOULD still keep the story in a more believable atmosphere. That would explain the hiccup in the story by switching to the term "Landlady" instead of "Mom" or "Mother". (It couldn't be more plain.) Yet, Patreon told you to keep it away from incest. The entire story revolves around YOU and this "Landlady". With that, let me begin with the obvious. Proofreading it before publication never hurts.
It wasn't TOO bad, but definitely needs work.