The Republic of Ireland's state pathologist is to carry out a second autopsy on the 21-year-old's body
An earlier Spanish post mortem examination concluded he had died from multiple organ failure.
His friends claimed he had been beaten by Spanish police after he was escorted from the plane on arriving in Ibiza.
His family said they want answers about his death.
Seven of his friends have made statements to the Police Service of Northern Ireland.
The body of Alan Drennan, the County Antrim man who died in Ibiza last week, is due to be flown to Dublin later on Tuesday.