Sounds like it was good news.
Don't know if this will help, but a few weeks ago I was really stressed out, and I prayed that God would restore my peace. A day or so later, dh and I were babysitting 2 of the littlest grandboys and I found myself sitting in the back yard, watching toddlers and puppies and slowly blowing soap bubbles into a light spring breeze. All the stress just drained away as I realized that all those things I'd been anxious about were either something I had no control over or were not that important.
Everyone has to understand that in their soul; it's not something you can tell them. But when we realize -- really realize -- that the things we're stressing over either are beyond our control or not really important in the grand scheme of things, it enables us to let them go. Peace restored.
I'll pray that your MIL comes to that understanding. Hang in there, CaryC, we love you guys, and the Lord is always as near as your breath.