I'm sorry to hear you are having such difficulty with your MIL (glad mine isn't like that) The best advice is to just give her time to cool down and try to approach her again. If Isabol is being abused or neglected then I would call the authorities right away. I would say catnap her, but then that just makes you as bad as her, and you're better than that.

Not to be nosy, but why is she POed at hubby?

Sorry I can't be more help.