You have a very compelling story title; just reading it brings a bittersweet sorrow. This is the first time I've read where Frank was the fifth roommate (JKR herself said that that each house had five boys and five girls in each year.) And as what happened to Frank "was worse than death", it fits that he would be the fifth. Nicely done.
Author's Response: Thank you very much. The contrast between their childhood and adulthood always strikes me hard.