It's not possible at all, first of all how do you form a consensus that this money is actually all lost? There is a high possibility that this might not be lost, it's just that owner must have kept it safely and securely person saying he has the key and lost it might be lying even if you realise that it's true you'll have to cheat the system protocol in order to get this money which not only sound unethical but foolish at the same time, so I don't think such a thing would happen.