Your calculation is wrong. He would have lost that much if he would have sold. You know the profit/loss only when you are on the same coin i.e. after conversion is done for real.
He sold only (heh, only?!!!?) 8 000BTC of the
We are not losing any single cents until we sell our bitcoins because only the value has decreasing in downtrent but not volume,so as long as we are having the coins we are not losing anything at all