Look, there is an answer to what you're asking, of a sort but, it isn't a satisfying answer.
Scientists have worked out that a cell can only hold one virus at a time and good old rhino virus (the common cold) actually evicts covid from cells and it fights off covid. It's counter intuitive though because covid can kill us but, the common cold doesn't normally kill us, yet, the common cold can beat covid in a battle to control human cells.
So, an old man gets covid and he is dying. His weakened body is then hit with a cold or flu variant and the battle to control his cells begins. He dies and a brief autopsy shows covid and a flu or a cold. Doctor/coroner attributes his death to covid because covid was present.
