if he could dump his that much of bitcoin and moreover in that time where the valuation is deflating then most probably, this is his greed or he could be in need of some money that he needs urgently otherwise selling bitcoins at very low rate is never justified because this is the time of holding of bitcoins. He could be dealing with some kind of stress that forced him to sell his bitcoin at the time when the valuation is very very low otherwise there will no such person who will bear such a huge amount of loss that he could dump his 250k worth of bitcoins.