Not sure which is grosser: if that discolouration was caused before or after the death. I don't think they'll get their asking price for that, though. Assuming it isn't just meant to troll christians into thinking they missed the rapture.
Possible to an extent I suppose, though with the clear silhouette of the whole body, that seems like it would entail a lot of nude usage for a chair in a "family" area.
Idk, if this is the original placement of the chair, usually there's a small ash tray near by. A long term smoker doesn't use plants because it's piles up. Looking at the bright lights above the chair, my money is on reading chair. Probably heat or light damage.
if the room had full sun visibility and the windows didnt filter UV light it could just be somebody sitting in the chair for years in daylight and the darkening is from the chair getting more sunlight. Especially if the room only got lots of sun in say the morning or evening