Sara (the Zohar says) is the body and Avrohom is the Soul, yet, Avrohom 1) listens to her 2) mourns her, as she is the purpose.

After Sara passes away we see her live. Her life is about the Jewish people exclusively while Avrohom is about all of humanity. This shows itself in each of the big events in this Parsha.

Toras Menachem vol. 4 page 127ff

Chayey Sara 5720, Toras Menachem vol. 27 page 146 ff.