I'm surprised her mom told her about the cancer diagnosis. My mom refused to tell me what her diagnosis was when she was in the hospital with serious symptoms. I got wind of her hospitalization from "worldly" relatives. My mom was so angry that I'd been informed that she refused to tell anyone what was wrong wih her for fear that it would get back to her df'd kids.
I've been out and shunned for 25 years, so I find none of this as shocking. Over time I'v come to realize that shunning isn't that difficult for gung ho jws, because they're conditioned to let loved ones and even themselves die over the blood issue.