Tyler Kerry was last seen by his brother and cousin asleep on a sofa in the hotel’s lobby.
They left him for “a few minutes” to get a drink but when they returned he was gone, with his T-shirt and jacket left behind, Mrs Kerry said.
Two members of staff pointed to the lift shaft when asked if they had seen him, she added.
Mr Kerry said his grandson’s trousers and a vape, covered in blood, were found on the first floor of the hotel.
The couple said it had been “extremely frustrating” trying to get answers from hotel staff and police in Turkey and said at times it felt like they were “banging their heads against a brick wall”.
Mr Kerry’s body is being repatriated later.
The has contacted Turkish police for comment.
