A boy and his bike

On Sept 13, 2014 my son was hit by a car while riding his bike. On Sept 22, 2014 i was told that we might held accountable for his medical bills even though the driver of the car has admitted fault. I don't know what to do with my anger. I'm angry at the driver of the car, i'm angry at God for letting it happen, I'm angry for everything my son has to go through, and I'm even angry with myself. I keep asking myself What If? What if i had been paying closer attention? What if my son had never chose to ride his bike with his friend? What if the driver of the car was younger and better in control of her car? What if we had never moved here?
Ever since that night i cant get the image of my son flying around in the air like a rag doll and landing on the ground out of my head. I cant get the sound of my son screaming, or the impacting sound of the car hitting my son on his bike out of my head. I am having sleepless nights worrying about whats to come for my son in the future. I wake up in the middle of the night to make sure he's still breathing, and not having seizures. (a common symptom of concussions I'm told). I lay awake at night and blame myself for it even though i know its just that, an accident.
My son still wakes up screaming from nightmares he has about the car chasing him. he has started wetting the bed again because the nightmares have gotten so bad. I feel helpless because i don't know how to take care of something like this other then to reassure him it will be all right. One of the many other things he has shown since the accident is the unconditional fear of moving cars now. My son used to love looking at cars, watching them slowly drive by with an look of aw on his face. Now since the accident if any car is moving he goes stone cold and refuses to move until the car has passed.
My son and I walked down to the house of the driver because my son requested to meet her. She defended herself, blamed my 8YR OLD son for the accident, tried making me feel pity for her, then apologized after everything was said and done. She even went so far as to say my son was playing chicken with the cars. Hes 8; he doesn't even know what the game chicken entails. Part of me wishes this had never happened to my sweet, innocent, precious boy. But the other part of me feels horrible for being glad about it. I'm glad about it because he is now more aware of the danger lurking at the end of our drive way. He is now more cautious when he is outside. We now know he has the same neurological condition i have, thanks to the lovely ER visit with a CT scan. but every time i look at the positive in the whole situation i feel horrible for it.
I wish i could jump into the blue police phone box and go back to Sept 13, 2014, find the boy and his bike, and pull him back from the edge of the street before the accident.
Until then i will remember my son before the accident as such: a sweet, innocent, vibrant, fearless, 8yr old boy on his bike enjoying the wee last bit of summer with his friend.