When Harry and Voldermort are dueling with each other there spells hit each other. This causes the victums of Voldermorts Avada Kedavra curse. First its the Hand from Wormtail (Peter) then Cedric, then the old muggle from Little Hangleton, the one witch(I havnt read in awhile) then his father, then his mother. If it was supposed to be reverse order then his mother should have appeared first. His father died before she did. He fought Voldermort and told her to run with Harry. Just a slip up I noticed awhile ago.