Kids are way too expensive and two kids at the same is some lvl of noise I doubt he'd accept, when he barely stands one. Even if he somehow doesn't catch on that it isn't is (as far as we're aware they've clearly not been intimate in ages), it sounds like he'd ask her to abort it. If he doesn't crash out over the fact she hide it from him.Was he away? other than work there was a complaint about him just not 'contributing' to the childcare and like telling her to get him (baby son) to quiet down which lead her to driving him or so, versus "we haven't been intimate since baby was born" but i imagine that's not something the mom/grandma would have knowledge about/talk about that openly with the sister, if not some flimsy excuse like "it happened when you were drunk/dead tired" or him not noticing/caring b/c she's gonna do all the 'parenting' anyways
She's most likely going to end up as a divorced mother of two.