The balloon would also probably go into a sideways attitude -- since aerodynamic drag would be minimized that way as it was zooming upward.
Someone just called Hannity’s show, and did some rough math on the volume of the balloon, looked up the lifting capacity of helium, and suggested that it was HIGHLY UNLIKELY that that balloon ever carried that boy anywhere at all- since it didn’t have anything like the capacity to lift the average six year old boy.
Witnesses notwithstanding, I think the caller might be on to something there.