The Gates Ajar by Elizabeth Stuart Phelps
When Mary Cabot loses her beloved brother in the war, she feels as though she will never feel peace again until the arrival of her widowed Aunt Winifred. Sharing the wisdom that has comforted her through her grief, Winifred offers Mary a groundbreaking view of the afterlife as a place of loving reunion with all those who were lost. Winifred's vision of the afterlife circulates within the community and attracts local adherents who have also suffered great loss in the war.