A person has been missing for years. Life was previously established, and death has not been adequately proven. Presumption of continuity (istiṣḥāb) can preserve certain pre-existing rights, but deriving every new benefit or entitlement from that presumption is a separate issue.
The distinction between defence (dafʿ) and affirmative imposition (ilzām) is crucial. In defence, an established position is protected from an unproved challenge; in imposition, a new right or liability is asserted against someone. Classical Hanafi discussion emphasizes the former use of istiṣḥāb.
Caution: Preserving a missing person's existing property is not the same inference as awarding a new inheritance claim.