In 1938, Helena Victoria and Marie Louise' s only niece, Valerie Marie (natural daughter of their brother Albert), requested her aunts to sent a letter attesting she was daughter of their brother, so she could marry a German nobleman.
Helena Victoria died on March 13, 1948 when she was almost 78 years old. Marie Louise survived her sister 8 years more. In 1856 she published her memories with the title of "My Memories of Six Reigns", including her remembrances of the reigns of her grandmother Queen Victoria, her uncle Edward VII, her cousin George V, her nephews Edward VIII and George VI, and Queen Elizabeth II. She died just after the publication of her book, on December 8, 1856, when she was 84 years old.