I am no pharmacist, but I would imagine there are drugs which could cause almost anything. Because of where he was found, I do not think his death was from natural causes.They don’t give us any idea any recognizable cause of death so far, so anything is pure speculation. However, with all the mystery deaths in the scientific field. it does tend to suspect an anti-American to me.
Maybe he got cold and crawled into a dumpster to get warm and died in there.