Eitan Biran’s parents and younger brother were among the 14 people killed when the gondola they were riding in plunged to the ground in Italy in May.
But since the disaster the two halves of his extended family have been locked in conflict over who should look after the orphan.
A Tel Aviv family court held its first hearing of the case on Thursday behind closed doors.
After the cable car crash, an Italian court ruled Eitan – whose Israeli family were living in Italy at the time – should live with his paternal aunt near Pavia, in the north of the country.
But in September, Eitan’s maternal grandfather Shmulik Peleg picked up the six-year-old for a planned family trip before flying him back to Israel.
The aunt, Aya Biran, has accused Mr Peleg of kidnapping her nephew and filed a legal claim seeking his return to Italy and her custody.
But Mr Peleg has insisted “we departed in a totally legal way” and told Israeli media he was acting in Eitan’s best interests by bringing him back to live in Israel.
Ms Biran was present at the court hearing in Tel Aviv and told reporters outside she was desperate to bring her nephew “home”.
“At this point I am worried. I want to see him home as soon as possible,” she said. “I am worried for Eitan.”
Mr Peleg also attended the hearing but did not speak to journalists. However, in previous interviews he has said the six-year-old was “in the place he is supposed to be, in his home, in Israel” and happily surrounded by family members.
“I believe that one day Eitan will grow up and say grandfather, you did everything for me, you saved me,” he tearfully told Israel’s Channel 12.
“And my daughter, who one day will meet me in heaven, will be proud of me that I saved her son.”
In a joint statement, lawyers for both sides said they had agreed that the child’s wellbeing was paramount.
Ronan Dlayahu, representing the family in Israel, called for the boy’s privacy to be respected while Shmuel Moran, representing the Italian side, said the sides had agreed a temporary arrangement for visits pending a custody decision.
Prosecutors in Pavia opened a kidnapping investigation after Eitan was taken to Israel, and Israeli police have already questioned Mr Peleg over the matter.
It remains unclear why the cable car, which was running on a line connecting Stresa on the shores of Lake Maggiore to the nearby Mottarone mountain, plunged to the ground earlier this year.