It depends on at what price the one sold his/her bitcoins. If he/she sold at 19000 dollars, they made a huge profit and they are still not in a loss.
Yes it is. It depends on what price did he/she bought bitcoin but he/she can use it in investing to other trusted mining company. You should be wise and think another way to not go to loss of money/bitcoin. But also they can be patient and wait till the bitcoin price rise up again.