road traffic accident

my brother is 20 years old. he was involved in a car accident in may 2008, where he was coming from a give way n hit an oncoming vehicla , in his courtsy car. the thrid party is now claiming vehicale damage n personal injury. he was insured fully comprehensive, however, they will not pay out as the belive that his satament is not true. therfore the case as gone to a civil court.
he was then involved in another car accident in october 2008. he sustaineda serious head injury which has left him physically weak in his left side, and with memory issues. hes lost his memory for the 2 previous years upto the accident and also has problems with short term memory loss. i jus want to know whats the best way to go about this.