To make a long story short I have an estranged relationship with my sister. We grew very much apart after our parents divorced. I don't want to get too much into detail but she did something so awful to me that I haven't spoken to her in almost 10 years. We are now both adults living thousands of miles away from each other and I'm physically, mentally and emotionally prepared to go on like this for the rest of my life. She could die tomorrow and I honestly could care less, I probably wouldn't even go to the funeral. Is this haram according to Islam?
*She is a non Muslim by the way