Sadly JWs look to earthly men to set rules for them. The Shepherds of the flock are supposed to tend the their sheep, not to lord over them. The term Governing in Governing Body should be apparent enough that they have taken on a role that was not assigned to them.
This is a real test for your mother and she doesn't want to disassociate from you. I imagine she may need to talk to other JWs about her feelings, maybe even the elders, if she decides to cut off contact then she will be forced to go against what her own conscience and heart is telling her. This is very wrong for the GB to impose this on her in order for her to remain a JW. I understand why many need a church/congregation in order to feel they are serving God and doing it as part of a group fills a need, it is natural for many but the GB enforce their own rules and there is no option for many. Unfortunately, what these individuals are doing is obeying men's rules rather than those rules set down by God, but they don't know it and it is wrong.
I so hope that she allows you to discuss issues with her in far greater depth so that she sees the manipulation and control that the GB through their organization are seeking. The recent WT issue on the FDS is great, the January article on the generation teaching is ideal as it's just so easy to discuss the falicy of it.
Thanks for keeping us updated.