how is he a dummy?
do you know how much he invested and at what price he bought in it?
if he’s at a loss and panic selling then I’ll admit it’s not the best move
but if he’s trying to protect some profit and looking to double dip if BTC falls lower then it’s a risky/aggressive move that can pay off more or at the very least allow him to walk away with some profit
Because BTC will rebound even greater you and I know this... Then he's gonna be mad he sold too early!!! Dont get me wrong he has every right to sell but id wait.