Denmark’s Crown Prince Frederik has cut short his visit to the Winter olympics in Pyeongchang to return home to his sick father, Prince Henrik, whose health has deteriorated, the palace said Friday.

Henrik, the 83-year-old French-born husband of Queen Margrethe, was hospitalised in Copenhagen in late January for a pulmonary infection and a benign tumour in his left lung.

“His Royal Highness Prince Henrik’s condition has unfortunately seriously deteriorated,” the palace said in a statement, adding that the crown prince, 49, “is now on his way back to Denmark.”

Prince Henrik was diagnosed in September 2017 with dementia.

The palace never disclosed further details, saying simply that his illness “involves a deterioration of cognitive abilities”.

Born Henri Marie Jean Andre de Laborde de Monpezat on June 11, 1934 near Bordeaux, he married Margrethe, then crown princess, in 1967.

Henrik, who retired from public service in January 2016, has often spoken out about his frustration that his royal title of prince was never changed to king when his wife became queen in 1972.

Last year, he announced that he did not want to be buried next to his wife because he was never made her equal in life, thereby breaking with the tradition of burying royal spouses together in Roskilde Cathedral west of Copenhagen.

The royal couple also have another son, Prince Joachim, who is 48.