First the father of the DoE is Prince Andrew the younger son of George I of G.
Here with his brothers

He married Princess Alice of Battenberg

Her life seems to be interesting, I didn't know about her

they had five children, 4 daughters and a boy, the DoE
Princess Margarita of Greece and Denmark

Princess Theodora of Greece and Denmark
Princess Cecilie of Greece and Denmark

Princess Sophie of Greece and Denmark
I couldn't find photos for two of them, I have to search more
the one you say that died in an accident is Cecilie no? I will look for more photos of her
