"It was just a disaster," he said.
As well as Lillie, Willsher and Jackson, 10 other children and six adults were killed in the fire that swept through the Villaggio Mall.
The blaze has been blamed on an electrical fault but a court verdict into who was responsible is expected next month.
A memorial will be held overnight at Aspire Park next to the mall, where there will be a moment's silence before 19 balloons will be released.
Mr Weekes said a few hundred people were expected at the event.
"It will be interesting to see what happens because it is illegal to gather in groups in Qatar," he said.
A year after the tragedy, Mr Weekes is still angry about the official process that has dragged on.
The families of the victims had been promised a report into the fire, which they and the court were yet to receive.
"The report was commissioned by the Crown Prince, therefore it is his report. We've been promised that report from countless levels of authority, including the Attorney-General in Qatar, however, the only person that can release it is the Crown Prince," Mr Weekes said.