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24 December 2014 Last updated at 13:59 GMT
Billy Caldwell was aged just six months when his mother Charlotte was told by a Royal Belfast Hospital for Sick Children doctor that he would not survive.
BBC Newsline's South West reporter Julian Fowler has the story.
A Castlederg boy who has a severe form of epilepsy has been making huge progress thanks to the support of his local community and a Santa's grotto.