There's pretty much zero chance that a Granparents' Rights case will happen. Those laws only apply when the parent who is the grandparent's offspring is not in the picture - like, dead, in prison, had rights severed not in the picture. No legal entity is going to force LW to maintain contact with their MiL to keep the kids in Mil's life if MiL's son is present, parenting, and capable of doing the work of keeping MiL in the kids' lives (which her legal right to is sketchy to nonexistent anyway).

Unfriend/block away!