Hi Blackie I think you should stay at home with the w if your relatives are not going to be nice to her. If you think they will be OK then speak to them first and tell her they wanted her to come to see if you can convince her. Without invading her privacy perhaps you could mention that she is not well and you don't want her to be upset. But you should not leave her alone especially with the medical issues hanging over her head. Even tho you have been thru some tough times recently she should still come first with regards to your family. That might be something which will show her how much you care.
I'm sorry to hear about her health probs that must be really hard for her. You should try to have a talk about it and tell her you will be there for her and not to worry.