if that’s the wagering requirements in terms and conditions then this amount will be transfered to his bonus account.
usually casinos also put a max cap on the amount of bonus that can be won from the freeplay promotion.(ie $250).
after the freeplay promo, the winnings will be transfered to a bonus account. this bonus then has to be wagered usually 30 times before it can be withdrawn.
essentially the freeplay bonus is kind of like a deposit bonus based on your freeplay winnings, which is why casinos will not give you another deposit bonus if you won money in the freeplay promotion.
in order to withdraw a player also has to make a deposit.