holy crap this is turning wild, so the mom is plotting something else to try to keep the husband and a "family" even is she's just a cheating whore, seems she just wants the attention or something like that, with how she said she's lonely, even if she's one of the big causes this is happening.
And wow did not expect that bomb to be dropped just like that, can't belive if is true or not, he might be just messing around, but I could see happening some way, they're step siblings he has a different mom, but same dad as Moe, Akemi had the kid and gave him to adoption and the family kept it hush, until she Gotou hooked with the you got me pregnant so marry me; or pretty much he's just lying to trying to get to Moe in some way(?)
We don't have enough information as to whether this new guy is telling the truth in any respect.
He could very well be Moe's half-brother; her friend comments on how similar they look, giving
some credence to his claim. But we don't know why he claims that Moe isn't her father's daughter; we have no info on paternity tests done by the PI, so him saying "Goto's not your father, we share a father" is coming out of nowhere.
What we can surmise, is that everything he knows is from reading the files put together by the PI firm. We don't know the full contents of those documents & files, but I wager that paternity tests aren't a service provided.
So ultimately, it comes down to his motives and his aims, which we're not going to get this early in, anyway. Ultimately, he's another obstacle for Moe to deal with, though, and she might do so alone, which could be dangerous.
As for Akemi--there's a chance that this is alluding to Goto
actually being the father of her current pregnancy. Could be there's some fuckery in the works on her end to fake a test, but I'm not sure that's the aim. She might sleep around, and Goto seems to think this is her acting out because she got pregnant at a young age and they got/were forced to get married early and she "missed out" on her young adult years.
I'm still not sold on that being the reason she's a serial cheater, as it feels very superficial and like the sort of lie Goto would tell himself to ease his own mind about Akemi's infidelity.
But, Akemi did love Goto at one point, at least. She might very well seek to keep that family together, especially as Ken and Moe
are her children.
But again--nothing reay concrete to build off of at this time. There's a lot of moving parts at present, so we'll have to wait and see what these two new developments bring.