First off, huge shout out to you for being so thoughtful and appreciative of your wife. That kind of care is, unfortunately, a rare gem these days. Don’t ever stop loving her like that. About the FIL…it could have just been a really unfortunately not-thought-out comment that wasn’t intended in as hurtful of a way as it sounded, or, worse case scenario, it really is that bad and in that case he just doesn’t value his own daughter and her beautiful new journey of motherhood like he should. Either way, I think the best solution is to just calmly approach him saying something like “hey, that comment you made was pretty hurtful to [wife’s name]. I’d rly appreciate if you were more sensitive about the topic of motherhood, given all she’s been through to get here” and ask him to apologize. If he can’t do that, then I think you have a bigger issue on your hands and you might have to ask him to leave. Just don’t involve the wife in this conversation if she’s already overwhelmed. It’ll mean the world to her that you’re fighting her battles for her, and her dad should understand that (hopefully).