That sounds like a solid observation. I often like to keep in mind that mostly what people say is a reflection of them, not of anyone or anything else, no matter the topic. That's not to be mean or anything. It's just the reality of spending all our time in our own heads!
Nonetheless it's tough, especially in your position. If ever you could play the cancer card, now would be a good time.
You could always meet her opening question with cheery "No! Not going to talk about cancer today" and instantly hit her with a series of questions about her troubles. Generally speaking we all like to talk about ourselves! K xox