Who is Laurence Macy III from The Egyptologist and what is their importance?

Laurence Macy III requests information about his aunt who recently died, Margaret Macy, the former Margaret Finneran, from Harold Ferrell. Macy does not write anything directly but compiles and apparently arranges Ralph's journal entries, letters to and from Margaret, telegrams, notes and Ferrell's letters. This material appears to be unedited, a technique that makes the novel seem more authentic but does leave loose ends dangling.