From what I have read on PCS, it is fairly common to have delayed symptoms. I experienced the same thing. I felt really bad at first, then felt better, then started feeling really bad for a while. From what you have described, it sounds like a textbook case of PCS. The second hit was most likely what caused it. The brain did not have time to heal from the first hit and it was in a weakened state when hit the second time. Like the others said, the recovery times vary widely. Most people are fine within a few weeks to a month. Some people take 3-6 months and others like myself take even longer than that. She needs rest, and recovery may be a slow process. There is not alot you can do besides resting. When she starts feeling better, you should let her gradually go back in to her normal activities. Too much activity could actually make it worse. Don't worry yourself too much over this. She will get better. You just need to give it some time.