What Causes Memory Loss And Confusion Followed By Nausea And Chest Pain?

My husband has been in hospital and discharged without a diagnosis. He initially went to hospital with memory loss and confusion. On arrival at hospital he started feeling nauseous, followed by chest pain, pain in his left arm and then a severe headache, the pain seemed to be in various places over a period of time eg. front left eye into the upper side of his left forehead, then it shifted and his neck also became stiff, with a sensitivity to light and the pain seemed to be in the back of his head. The headaches have now continued for five days.