I've been approached by a friend/neighbor who wants to write a book about her adopted son. She is an upper middle class white woman raising an African American boy (12 now) who was born a crack baby and suffered sexual abuse. She feels compelled to tell her story about raising this beautiful child because she couldn't find any written material about parents who'd had the same experience or inclination.

Though I'm a fiction writier, I have a history degree and experience in research and writing theses. My plan is to have her tell me her story (with tape recorder, white board, and my laptop) so I can capture everything she wants to say. I also plan to do research, fact check, possibly do interviews, etc.

My question is: Has anyone experienced writing someone else's story before? Should I write this family's story as a memoir? If so, can a memoir be written with a specific purpose (i.e., she wants to tell her son's story to raise awareness about crack babies and abuse, as well as for the benefit of people who may want to adopt older children)?

Any and all advice is very much appreciated!