Khudida Haji has followed news of the battle for Islamic State’s final stronghold more closely than most.

For four and a half years he has been hoping for information on family members captured by the jihadists. Out of the five that went missing the day Islamic State of Iraq and Levant (Isil) overran the Yazidi homeland of Sinjar, northern Iraq, in 2014, only one returned.

He had clung to the outside chance that his wife, two daughters and youngest son were still alive and being held in the group’s ever-dwindling territory.

But when it was reduced to less than a square-mile in the Syrian desert, he was forced to confront a more painful possibility.

“With every day that passes, my heart grows…