My brother and I play on a world together, via LAN games, and I killed him, and he dropped none of his items. He dropped his 7 levels, but none of his items. We searched everywhere around his death point and found nothing. He had netherite tools and armor, shulker boxes of resources, and other things. I killed him with one hit of a netherite sword and a bow. He right clicked a chest right when he died, so that might have something to do with it. Please upvote! I wouldn't want this to happen to anyone else!