Jokes and sarcasm aside did we in the story ACTUALLY confirm the MC is the father? It the loosest of proof that a letter from a woman he met that one time telling him he was the father but we role with it because the "tenants" are hot
The letter changes if you play w/o the patch (or the Taboo-no incest version). It's not explicitly stated who the girls father is but you are implicitly acknowledged as
not the father. i.e It's not the same letter with a shitty "Ctrl F" word substitution with "tenants" in lieu of daughter etc making no sense whatsoever. There's an alternative variation of the story.
IIRC, her daughters are destitute, you're rich and as the one person who she believed cared for her (and on her side, kind of a Sarah Conner/Kyle Reece - only 1 night, but love forever kind of deal), she asks that you have it in you to take them in as wards. The girls also have some different dialogues scattered about recognising that MC is under no obligation/acknowledge that it's a huge burden but mom believed that he was their last/only choice or words to that effect, call him guardian (not landlord) etc. The MC's internal dialogue is also different when contemplating the triplets.
It's been a long while, so it's a bit fuzzy (I experimented with no-I for the Dark path figuring it's more "palatable" to go full dark if playing as an MC resenting the fact that children of some subsequent rando have been foisted on him, but it means having to have two copies of the game and that version is currently deleted from my HD.)