Mom called today and said "we needed some time, but just lately we are more at peace with whatever is going to happen. W can come up with the family this weekend if she wants to"
That's good. Like I said, it hurts the hearts of parents with grown children, just like the ones with very young children.
I'll throw this in also, parents of adults learn to tolerate a lot more than they ever dreamed possible...simply b/c they want the son/daughter to be happy. It's not easy to put up with an in-law who is a ring-tail tooter...much less deal with them when they've inflicted pain to your child.
So, now they have had some time to deal with their own emotions and realize what they have to do......and, that's to tell their DIL she's welcome to come.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!