I see your point.
But I still haven’t seen any clarification about the location of the pillow.
“Over” his head could mean above his head between his head and the headboard.
I think he went to bed and just died.
But we can put nothing past the Evil ones.
That is probably just what happened. The suspicious ways in which his death was handled will only add fuel to the conspiratorial accusations. The cynic in me would not be surprised to learn that murder occurred.