I was being tactful before - tact does not come easily to the brain injured!. Maybe you could tell your son that when I was 14 I hit my head on the bottom of a swimming pool, then at 16 I was knocked out playing hockey - I got better - then following all this is those accidents that you can not predict or do anything to prevent - my car accident at 21 and then all the little knocks in my 30s and then the tiniest of knocks in my 40s - less than any of the others that have resulted in how I am now. My last concussion 3 weeks ago was simply brushing the top of my head on the top of the door frame putting things in the car. In truth I don't think anybody could have warned me about this when I was a teenager but your son has been "lucky" enough to have been warned. Hope I don't sound like a drama queen - your son will think he is being nagged - tell him it is because none of us would wish how we feel on anybody!! By the way my name is really Lynlee.