What gets me, though, is that is not enough helium to lift even a 30 pound child. He looks a bit heavier than that as well.
You'd think that in the big brouhaha someone intelligent would have been consulted, calculated the lifting capacity, and noted that either he wouldn't have gotten off the ground, or if he had (and maybe was emaciated) he certainly wouldn't have gotten up to 7,000 feet.
The father knows the exact lifting weight of the balloon.
There is simply no way he could have thought his son was actually on board.
-Adam
---------- Post added at 12:25 AM ---------- Previous post was at 12:19 AM ----------
The balloon was apparently 20 feet in diameter, 5 feet high, which is 1570 cubic feet of helium, or 44 cubic meters.
Each cubic meter lifts about 0.2 pounds, so that balloon, like most weather and instrumentation balloons, can lift about 8.8 pounds. The balloon itself is a pound or more, so the family cat couldn't have hitched a ride.
There is simply no way the father could have ever believed that his child was on board.
-Adam