FMIL has pretty much lost her shiznit. Without going into too much detail, she's taking the view that FH and FBIL have disowned her as a mother by going to their father's wedding and so she's flouncing off to Florida to visit her mother.
But her mother, despite not really liking FFIL even before the divorce, is not inclined to take her side. No doubt she'll spend her entire stay texting FH nonstop, so that should be fun.
The one good thing about all this is that FH has finally gotten tired of mediating his family's nonsense and is washing his hands of it. We'll see what happens.
*sigh* the crazy was a lot more bearable when she was just being racist about me.