Correct. Everyone else will simply get out a calculator or crack open a spreadsheet and go "brute force" just to make sure they aren't dribbling horse excrement rather than calling all who disagree idiots.
Yes, sadly people like this have to lose everything before they have a chance of learning. By the sound of it, he has already begun that path in his life, and it will get worse before it gets better. Its like the alcoholic who must "hit bottom" before he has a chance of recovery.