"We have hoped that Prince Friso will recover again, " said Mayor Ludwig Muxel.

CNN: Dutch prince suffers brain damage after avalanche

In February last year her second son, Prince Friso, was struck by an avalanche in Austria and remains in a coma.

BBC: Queen Beatrix of the Netherlands to abdicate for son

The 2002 death of her German-born husband, Prince Claus, took a toll on her, and it was apparent how deep her reliance on the quiet man had been: she was filmed leaning heavily, almost hanging, on Prince Friso's arm as they entered the church for her spouse's funeral.

NPR: Dutch Queen Beatrix Abdicating, Son Will Be King

However the king's brother Prince Johan Friso lost his place in the line of succession when he married Mabel Wisse Smit in 2004 without parliament's approval.

CNN: What Dutch 'bicycling monarchs' can teach world's royals

Tragedy struck again in February 2012, as Beatrix's second son, Prince Johan Friso, suffered a skiing accident and fell into a coma from which he is yet to emerge.

BBC: The Netherlands' love and respect for Beatrix