Does anyone know a lot about comas?

My friend today had a terrible accident. Im 15. Here's what happened: My friend kyle was skateboarding and our other friend was driving away, kyle grabbed onto the car without the driver knowing. As his speed got higher the skateboard started to wobble and flew under the tire and broke in half. Kyle fell and slammed his head on the car then on the concrete. When he got air lifted he could breathe on his own and was responding and talking normally. But when he got to the hospital he slipped into a level 6 coma. He has brain activity but he can not talk or anything. He just turned 18 about a week ago. He is very Strong willed and has a hard head. He has a little internal bleeding in his head but no broken bones. What do you guys think? Im freaking out, hes like my brother. Im praying like there is no tomorrow.! What do you doctors and nurses out there think? Do you think he will pull through? Im so worried so if anyone makes a rude comment to this you have no heart. PLease help! :'''''''''''( And don't be afraid to tell me straight up, i need to know what you guys truly think!