In the book Jacob Have I Loved, how did the main conflict affect the ending?

In Jacob Have I Loved, the main conflict was the bitterness and jealousy that Louise felt toward her twin sister, Caroline.  Caroline got more attention and praise when they were growing up.  At birth, Caroline was weak and sickly, while Louise was strong.  Caroline was given excellent care and attention as a baby because of this.  In the story, Louise described her feelings about their birth:

I was the elder by a few minutes.  I always treasured the thought of those minutes.  They represented the only time in my life when I was the center of everyone's attention.  From the moment Caroline was born, she snatched it all for herself (Chapter 2).

For many years, Louise held onto bitterness toward her sister.  She was envious of the praise and attention Caroline received.  Caroline was fair and beautiful.  She was a talented singer and often belittled Louise.  When they grew up, Caroline studied music and Louise became a midwife.  One evening, she delivered twins.  One twin was strong, but the other was weak.  She attentively cared for the weaker twin.  Then she remembered the other twin.  She recalled how she had been left alone at birth because she was the strong one.   She called attention to the other twin because she did not want him to be alone.  Though Louise cared for the sickly twin with compassion, she also made sure that the stronger twin was remembered.  She told his grandmother:

"You should hold him... Hold him as much as you can.  Or let his mother hold him."