Is zakat on money obligatory for a person who has been missing for years if his family has kept his money and knows nothing about him?

The missing person is not to be declared dead until after a period determined by the judge, not less than one year and not exceeding four years, while utilizing modern means and considering the circumstances. If there is no judge, then by the estimation of a group of just Muslims. Zakat is not obligatory on the missing person's wealth until after a ruling declaring his death. At that point, it is to be paid for the past years from his estate before its distribution.