The Sun throws lots of high speed protons around. Especially during its sudden and short intensive "events". Much of that is blocked by Earth's magnetosphere and atmosphere. But astronauts work outside some of those natural shields. Could a Sun event actually have disabled and killed an Apollo crew during flight? Or did their spacecrafts have sufficient radiation protection.
I'm not interested in shortened lifetime or other statistical cancer incidents here. But instead of whether there was a real risk of acute radiation sickness disabling the crew and becoming a serious risk to the mission. If they'd had bad luck with the space weather.