There has been a lot of talk about who might come back as ghosts in the Harry Potter series. I don’t think Rowling will have anybody return as a ghost, because she is very aware that there are children reading this series who have lost or about to lose a beloved family member to death.
When OP came out, my 36-year-old sister-in-law lay dying of breast cancer. She had three boys, 7, 9 and 11 year of age. The oldest, Alex, was a big fan and was very eagerly reading OP. I remember discussing with another sister-in-law whether we should tell Alex’s father about the discussion about death in the book, as he was involved in round the clock care of his wife at that point and of course had no time or interest to read the book. We concluded that JKR had done an excellent explanation of death for us. She conveys that to die and to accept one’s death takes courage, and that there is hope that we may see them again, as in Harry’s conversation with Luna. Two weeks later, my sister in law was dead. I like to think that Alex’s reading of OP may have in some small way helped him to adjust to this tremendous loss.
The other group of children that JKR is writing to are those children who are facing death through illness. In my case, although my children enjoyed the HP series, I did not read them until my third child, second son, was diagnosed with Leukemia when he was 15. He had to deal with the fact that some of his friends in the cancer ward have died, and although he is in remission right now, death is very much a reality for him. He had to spend much of his high school years in hospital, undergoing very painful procedures, isolated from other teens. When he went to live in a dorm for his first year of college, (against the doctor’s orders, because his immune system was so bad), what helped him was the fact that at a Halloween party his first year there, other students told him he looked like Harry Potter. He is on the small side, thin, blue eyes, and thick dark hair. He became a big fan of the books, and so I started reading them too. I can identify very much with Molly as the mother of nine children, and living every day with the thought that I might lose of one of my children to an illness which is random and very difficult to fight.
I really want to credit JKR for not avoiding a difficult subject like death, but instead has Harry ask what happens when you die. Her answers through Nick and Luna are insightful and profound.