ROME—A six-year-old boy who was the sole survivor of a cable car crash this year in northern Italy is at the center of a bitter custody battle between his maternal grandparents in Israel and his paternal relatives in Italy, who claim the child was flown without their permission to Israel over the weekend. Fourteen people, including Eitan Biran’s parents and younger sibling, died when the cable car slammed into a mountainside on May 23 after the cable broke. After the boy was released from a Turin hospital following weeks of treatment for critical injuries, Italian juvenile court officials ruled that the child could live with a paternal aunt near Pavia, in northern Italy. But the aunt, Aya Biran, told reporters on Sunday that the previous day, Eitan’s maternal grandfather took the boy on an agreed-up day visit, then flew him without permission to Israel. She said the boy has been …