I don’t think you really addressed the true issue: Mother-in-laws are often not the same person to the daughter-in-law privately as they are in front of their son/family members. They often have a severe case of the “oh, she misunderstood me’ syndrome when you call her out on her truly territorial/hierarchical/demeaning behaviors and acts as if the daughter-in-law is an attention-seeking or money spending whore out to pollute her precious Angel baby, to whom she “used to be so close!”

The other common dynamic is that the son finally has found a supportive partner and has the courage to make decisions that his family is surprised by, and the DIL gets blamed (think of Yoko Ono or Megan Markle): despite all evidence and the son’s direct statements and actions (distancing himself from his now-upset family who is shitting on his wife, for example), his mother ups the rhetoric that it’s the horrible wife pulling on his strings, rather than he was chafing under their unspoken rules and relieved to be creating his own family.

The MIL is always oblivious to her own behavior, and acts innocent, wracking her brain as to what happened?! How could this terrible, surprising tragedy befall her? And oh! Deprived of grandchild visits! That’s even worse than not seeing her son for gods sake. I mean, she’ll sell her adult children for five cents for grandchild access.