Once again, he felt apart from his twin: truly apart. They were fraternal twins, and therefore not genetically identical. They didn't share those feelings that identical twins often spoke about—feeling pain when the other twin was hurt, knowing when they were in trouble—but right now he could feel his sister's distress. He only wished there was something he could do to ease her pain. (33.72)
"And have you a grandmother?"
"My Nana, yes, my father's mother. I usually call her on Fridays," she added, realizing with a guilty start that today was Friday and that Nana Newman would be expecting a call.
"Every Friday," the Witch of Endor said significantly, and looked at Scatty again, but the Warrior deliberately turned away and concentrated on an ornate glass paperweight. (36.21-23)
Josh knew deep down that he had lost his twin, the constant in his life, the one person he could always count on... Even when Sophie's newly Awakened senses were making her sick, he was jealous of her abilities. (37.27)