To think this is a bit nasty and to want it to stop?

[CailinDana]

I get on fairly well with MIL but she can be a little odd at times. Last year a cousin of my DH's (daughter of FIL's brother) had a baby boy a little before I had my DS. My PILs both expressed surprise at her having a baby as she'd said years ago she didn't want one, fair enough, but they also slagged her off a fair bit behind her back saying she wouldn't be able to handle a baby etc etc etc. No real reason for this as far as I can tell. When her baby was born they showed very little interest which I put down to the fact that they were excited about my baby but since then they have been really odd about the whole thing. MIL very very rarely calls the baby by his name, she tends to call him "BIL's grandchild" or "(cousin's) baby" which I find a bit nasty and unnecessary. It's not like I don't know the child, I've met him a good few times and the cousin and I talked a lot when we were pregnant over FB so there's no need to identify him IYSWIM, calling him by his name would make it obvious who he is. Sometimes she feigns forgetting his name which is just ridiculous. I say his name every time she mentions him.

AIBU to question MIL about this? I do want her to stop doing it as I find it quite uncomfortable, as I find it quite nasty and unnecessary.

Ask her if she has a grudge (sounds as if she has).

She sounds like a bit of a loon. I wonder if she a) resents the cousin for having a baby shortly before you, thereby (in her eyes, perhaps) taking some of the limelight away from you, or b) really hates the name they chose for the child and can't bring herself to say it. My dad really didn't like my nephew's name to start with, he used to call him Harry, George or anything but his (perfectly unobjectionable) name!

does the cousin know? How does she feel. It's nasty and out of order.

Both of those are a possibility I think Fetchez. I did feel like she resented the limelight being taken away from her a little bit, especially as the cousin gave birth before me. Since she announced her pregnancy MIL has said some really nasty things about her, including about the way she looks and it's quite out of character for her. It is seriously odd. Whatever her reasons are I find it very childish and silly of her to go on like this and it riles me up every time she does it.

I don't think the cousin knows. When we visited to see the baby she was quite positive about him although she didn't give him nearly as much attention as my DS. I feel bad saying nothing as I feel like I'm colluding in a way, if that makes sense?

But what can you say? Not much really. Just keep being positive and nice about the cousin and the baby and leave her to it. Is she ok with you?

She can be a pain at times, wanting to do things her way, but generally she's fine with me. The problem is I became fairly friendly with the cousin when we were both pregnant (mainly over FB) and hearing my MIL go on about her really pisses me off. I'm thinking of asking if she has trouble remembering his name, just in a jokey way.

I think she is jealous her BIL and wife were grandparents first.
next time she is nasty pretend you did not hear and ask her to repeat it, then if she does ask her why she is saying that. Do the same time each time she is nasty and she will soon stop. When she does not use the baby's name, keep asking her who she means and keep saying other relative's names. the go "oh you mean x, why did you not just say so". Again done repetitively she will get fed up and stop.
Can i ask what cousin is like -is she a high flying career type etc? Does it get up MILs nose that her BIls daughter has a great job and baby? It might just be a jealousy issue directly with the cousin. If she was a career type maybe MIL used to be a bit jealous and make herself feel better doing the "being a mother is the most important job in the world" routine, and now cousin has a baby this has pulled the rug from under her feet.

Cousin isn't really the career type but she did make a big deal when she was younger about the fact that she was never going to have children. It turns out she did that to get her husband's mother off their backs, which I think is fair enough. I do try to ignore any nasty comments but it's hard as it annoys me so much. Recently we were talking about teeth as my DS is teething and she commented "I dread to think what (cousin's) baby's teeth will be like." This is a direct reference to the fact that the cousin has very crooked teeth. I found it so nasty.

just ask her outright why she is so unpleasant about her.

MIL's a cow. End of story.

YANBU.

Perhaps there's a skeleton in the family's closest

There is some tension between MIL and her BIL's family but nothing major. They hang out together quite a lot and even go on holiday together. I'm pretty sure there's nothing between MIL and cousin. Cousin was a bit of a tit when she was a teenager apparently but who isn't?