Thank you for writing to us.
It seems that your friend has had what is called as a concussion on the head.
When the head gets hit what happens is that the brain hits the hard skull because there is no space for the brain to move around.
This is called as a concussion and the symptoms that result after a concussion are termed as post-concussion syndrome
These symptoms can last for months or even years and usually go away slowly over time but some symptoms may just be permanent.