>>2501445sorry to hear this anon, that's very sad. my advice would be to fill the grave with medium sized stones just until about to ground level, then put a few of the biggest/heaviest stones you can move on top of them, and then pile a small mound of medium rocks around it.
this will provide sufficient stones to allow for it to sink and settle while also pinning down and jamming all the rocks in the ground with the really heavy stuff. nothing will get into it that way. if you want you can dump dirt into it to fill the cracks. i personally would plant or transplant a tree or shrub over it as well but that's just me.
