By Anna Hodgekiss PUBLISHED: 04:39 EST, 9 April 2013 | UPDATED: 05:16 EST, 9 April 2013 A two-year-old boy who longed to be alive for the birth of his sister has lost his battle to a rare genetic disorder just four days before her arrival. Archie Watson died last Monday after suffering from Tay-Sachs, which causes deterioration of nerve cells, mental and physical abilities and a maximum life expectancy of four years. Now his parents, Bradley, 34 and Lauren, 27, believe he is watching over their newborn, Matilda Rose, as her guardian angel. A life cut short: Two-year-old Archie Watson suffered from a rare genetic disorder and died four days before his longed-for baby sister was born
@highlight
Archie Watson, 2, had a Tay-Sachs, a disorder that causes nerve cells to die
@highlight
Died last Monday in children's hospice after singing his favourite songs
@highlight
His sister Matilda Rose arrived on Friday, weighing 7lb 8oz
@highlight
Parents Bradley and Lauren believe he is now Matilda's guardian angel
Lauren
Lauren
His death resulted in @placeholder, who was due to give birth on April 7, deciding to be induced.
Archie Watson
Archie Watson
Archie Watson
We didn't want regrets and to look back having wasted two years we had with @placeholder.'