OTWO I think you might be on to something there!
If I were DF'ed and in the area (or wanted to pretend I was never a dub), I would be tempted to go to that Kingdom Hall and talk to your MIL after the meeting. What could they do?
That might be a neat idea for some subversive apostate collective action. We could go to a hall where no one knows us and where there is likely to be DFed people sitting at the back and talk to them after the meeting. That would put the noses of the elders out of joint and perhaps shame the other Witnesses who are shunning their former friends. Who knows it might start a trend and bring the whole shunning edifice tumbling down. Well one can dream anyway.