Why were the second and third volumes of Das Kapital published after Karl Marx's death?

The second and third volumes of Das Kapital were published after Karl Marx’s death in 1883 because he had left them unfinished at the time of his passing.123

While Marx successfully published the first volume of his magnum opus in 1867, the subsequent volumes remained in the form of uncompleted manuscripts and rough notes. Following Marx's death, his close collaborator and friend Friedrich Engels took on the responsibility of editing these materials. Engels organized and prepared the drafts for publication, resulting in the release of the second volume in 1885 and the third volume in 1894.231