Who is Rebecca in the book, J: A Novel?

Rebecca is the Jewish grandmother of Ailinn. Alive during the time of WHAT HAPPENED, Rebecca marries a Christian, Reverend Fridleif. He seems to want to take care of her. She ends up converting and does her best to keep in touch with her parents who are angry about her marriage. Her parents stop replying, leaving Rebecca to worry they have been killed. Her decision to go look for them causes Fidleif to turn angry with her. In turn, this causes Rebecca to leave their daughter, Coira, with the nuns of Saint Brigid’s, who warmly take Coira under their care. What ultimately becomes of Rebecca is unknown.