Most Helpful Guy
She doesn't want to pressure you when your father is sick, but it must be very difficult for her and her son to live with your family. Clearly going through her phone was only an excuse to split from you.
No one would stay THIS angry THIS long just because of a phone! She has thought about this for a long time, and when she is with her son, she isalso thinking about his future.
So it's not just anger! She's not likely to go back on her decision. I'd move out right away and see if she is willing to talk after you're no longer living with your parents..but I wouldn't be optimistic here.