How could he hold his head erect if not alive?
According to reports, his body wasn't recovered for 12 hours. He body could have been in the state of Rigor Mortis. According to medical sources:
"Rigor Mortis, a stiffening of the muscles, usually starts to take place at around 3 hours after someone is dead with full rigor occurring at about 12 hours after death. After the 12 hour mark the rigor slowly ceases and at around 72 hours rigor disappears."