Hi
I don't know if you did well or not but try to see things from her perspective. What would you feel if you are the only child among your siblings who took care of your parents and that your siblings don't want to be even bothered by your feelings of guilt?
Taking care of elders is not easy. I know, she did it because she wanted. But legally speaking, all the children are obliged alike. She did a great service by taking care of your mother. Believe me, it can be hard, too hard. Now, she is not asking much. She is asking for her brother to listen to her. She repeats things again and again. She has not called you for a while. But she is your sister and she took care of your mother. In other threads you said you feel alone. Sometimes, we need just to donate ourselves and give love freely. I know I always say we do not want to be abused or neglected or mistreated by others. But we cannot have a ruler to measure every single inch of love we give and ask for every inch of reciprocity. Sometimes we need to act with generosity and things start to flow.
Perhaps your sister needs to go to a psychologist. But perhaps she needs your reassurance, as well.
Sorry I am being blunt as I was talking to myself. Maybe it is not your case, but sometimes depression makes us to be self-absorbed. We claim nobody loves us but, do we love, really?
I am sending you a hug and sorry if my reaction is out of the blue