though he has such kind of belief, but he still sold it. seems that he needed his fiat at that time but if he did stick to it and not sell, sure, he will be a billionaire today. it goes to show that even if you have strong belief on this market, there are circumstances that you still need to sell because of your financial situation.
I think he believes in Bitcoin and sold his Bitcoin maybe he really needs fiat at that time. After all, he work to have money for daily needs. Maybe he does something to his salary like donations and whatever the amountnof BTC he sold is for himself or family. Based on what I read from
here, he is aiming for the history where a person in their town received Bitcoin as a salary from a government entity. Well, his salary is already deducted with the tax as what I have read.