There is a sort of closure when a missing person is found dead or alive. There is closure any time a question mark is resolved with a fact.
However, there is no closure to grief. Major losses leave a hole in the soul. The sediments of time layer evenly over everything, but the depression in the ground remains for your lifetime. WSJ (paywall, alas): Closure Really Is a Myth, A Stumbling Block to Grief - I know both professionally and from my own experience that the term “closure” isn’t only a myth, it’s an illusion that is counterproductive.