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Sheesh.
The simple answer is yes, you have to continue to be her friend. She's likely not going to live much longer, and she isn't one of the most important people in your life, so it's not as though this is an undue burden. See her occasionally and suck it up--you'll be glad you did when you're on your own deathbed and lots of people come to see you, a few no doubt out of a sense of duty.