Sorry I skipped over this without responding. It's unlikely he would have survived with of without a helmet. Styrofoam only can do so much. I'm sorry your friend's life was cut short. We should all wear helmets, but a helmet is unlikely to change the outcome of a truck/bike collision. Everybody take extra care out there. Like most sports, cycling can improve your physical condition and it can result in injury. A double edged sword, stay on the edge, so it can't come at you.