man missing

If a person has not been heard of for 7 years, there is a presumption of law that he is dead.

But at what time within that period he died is not a matter of presumption but of evidence and the onus of proving that the death took place at any particular time within the 7 years lies upon the person who claims a right to the establishment of which that fact is essential.

You can file a civil suit in the jurisdictional court seeking a declaraion in terms of Section 107/108 of the Evidence Act.