Back then many people doubled their Bitcoin this way and many lost theirs, where are all those Bitcoin today? Freebitco is still working till date, they must have big bags of Bitcoin now.
As far as I know online casinos like Freebitco and other casinos have employees that we often see such as operators and as far as I know there is a casino every year there are bookkeeping that must be calculated by profits and losses.
Well, every year they certainly calculate expenditure and incoming funds, if Bitcoin that comes in of course they will melt to be made into a dollar, it is all for employee salaries and others to the casino owner, Of course Bitcoin is stored in their respective wallets, and even then if they keep it, but if it is calculated, of course every gambler enriching others.