setting a target price is also a good thing that he can do because sometimes when the price increases, we can become a greedy and we still want to case a bigger profit. and if he use target price, he can learn that the price will not always stay at the high price but the price will get down and even it will down too deep so he needs to set the target price to sell his bitcoin and take the profit. and after he doing this, he can wait for a while to buy bitcoin again at the lower price.