Wow, that's just bizarre. Does YH agree that it's bizarre, but just isn't willing to stand up to her? It sucks that she lives close enough to be able to do this sort of thing.
My crazy SMIL who we haven't spoken to since Christmas recently volunteered to work our Winter Carnival at J's school I guess so that maybe she could pretend she's Granny of the year and see our girls. Joke's on her because we didn't even go because I wasn't gonna do a carnival with both girls and DH out of town working. I also had several friends tell me she was asking lots of questions about our kids and nobody would talk to her. I totally understand your pain and I am enlisting your aid to buy an island we can put them all on.
Ugh. I would just tell her you guys aren't going then since you don't have anyone to watch D and then "change your mind" last minute and not tell her. I'm sorry you have to deal with this shit. It makes me mad for you.