I am a relative of Martin Flavin's. He won the Pulitzer Prize for "Journey in the Dark." As Peter Devine mentioned, the three folks mentioned are the Children of Martin. Martin's father was Martin Flavin the first, who came to the United States from Ireland with his mother, Eliza D'Alton, and his sister Katherine Flavin (my great grandmother) after Eliza's husband, Capt. William Flavin, died in Ireland.
Sean is an attorney in California. Flavia and Martin have passed away.
Martin Flavin, the author, has written Plays, Novels and travel books as well as articles in various magazines. I have been able to collect most of his writings, except for his all his plays. He had three plays on Broadway at the same time in 1929.