What Causes Neck Pain, Dizziness And Fatigue After A Head Injury?

Hi, my husband drank to excess yesterday. After going to bed, he got up (assume to go to bathroom), however instead of bathroom went down hall and fell down the steps (about 13 wooden ones). He was out cold. My son and I couldn t move him to a couch, so we made sure he was breathing and pulse was ok. We surrounded him with pillows to sleep it off. This morning he got up with really sore neck. None of us know what organs hit on the way down. He doesn t remember. Now his neck still really hurts, and he s acting weird. Like extremely tired, dizzy, unbalanced. I don t know if he s still drunk or if he has a concussion. How can I tell?