Nasty daughter in-law

If you want to continue seeing your grandchildren I would be very cautious about "pulling her up" about her bad behaviour, sometimes you just have to bite your tongue and stew. You're right in that she's rude and obnoxious by the sounds of it but unless you want to start a feud where she has the upper hand regarding time with the GC, I'd be inclined to suck it up. You could have a word with your son of course but husbands of shrewish women tend to be under the thumb anyway so probably no joy there unfortunately. It's a fact of life that you can't choose your son's wife, some are lucky in his choice, you poor Pussycat, are not

I understand your anger and frustration Pussycat but pull(ing) her up over it would be a mistake.

You could though be a lot cooler and less forthcoming when next time you meet. Of course say hello but when ignored at the first attempt to engage her in conversation, don't try again and when you or they are leaving, say 'goodbye' in general without a specific goodbye to her.

Being a little less helpful, polite and kind may or may not send a message but even if it doesn't, you'll probably feel better for doing it.