NC for this...
It's DP's brother's 23rd birthday today and he's having a meal with all his siblings and partners. We're the only ones with a DC and with no babysitter, I've said I'll stay with DD so DP can go and enjoy his DB's birthday.
MIL has asked DB if he can can take her DD so his little sister (10yo) along. MIL is not an easy person to say no to. So now a 10yo is going along to a meal along with a bunch of people in their early 20's. She is going to bored, moan and everyone is going to have to mind what they say around her.
AIBU to think MIL is out of order for asking this? Knowing full well that it's not what the birthday boy would want. I feel sorry for him tbh.