Konstantin looks very frail!
Indeed. If I remember it correct there were already some rumors about his (frail) health.
I thought he was older, but he is 78 years old (b. 2 June 1940). Born the same year as his oldest sister-in-law Margrethe.
In comparison:
Margrethe (b. 16 April 1940)
Henrik (b. 11 June 1934 - d. 13 February 2018)
Benedikte (b. 29 April 1944)
Richard (b. 29 October 1934 - d. 13 March 2017)
Anne-Marie (b. 30 August 1946)