When we first heard about the UN scandal, we couldn't believe it, we really thought it was a cut and paste job being done on the internet. So we wrote to the Guardian newspaper and found out the exact dates when they ran the story, then we ordered back issues of those two papers. Even after receiving the info from the newspapers, we still tried to make excuses, we were in utter disbelief (30+ years in the Org) So my husband telephoned the UN itself and they confirmed that the WBTS was indeed affiliated for almost 10 years. We also got them to put this in writing for us and when their letter arrived we made sure that we kept the envelope with the UN postmark on the front. You may be able to make that phone call to the UN while your mother is visiting you and let her hear first-hand from the UN. Maybe then she will start to research this herself.
I hope she will see reason, but it may take some time, it took us over one year to really accept the hypocrisy of it all.
Twinkletoes