What do you say to a 9 year old girl?

I live in a small community, and my kids are active in scouts, sports, etc. The husband and father of a family I know was killed tragically in a plane crash last week, with his wife and 4 kids there watching. They were taping, as it was one of the first flights with a new plane that had mechanical issues mid air. The family saw the plane go down, as well as 3 other girl scout families that were there after a scout ceremony. It was traumatic and devastating. I am hoping to go to the memorial, as not only is it a fellow scout family, but his youngest daughter has been in my son's class for years, and I have interacted with them all on a regular basis. His 2 5th graders are special needs, so I am not sure what they all comprehend. Mainly, what do you say to a 9 year old girl who saw her father die? I know "everything happens for a reason" is silly to me. I am heartbroken about this, thank you