Coming right down to the basics, however, is babysitting Dawn much different from nursing and protecting Dru the way that he did in Season 2, only, of course, without the sexual element. It's been said time and time again, Spike is NOT your typical vampire. Even when he was evil, he was compassionate and protective of someone who he cared about. Can you imagine Angelus taking care of Dru if he had been in Spike's place? Granted, Spike used to eat little girls like Dawn, but, as of Seasons 5 and 6, He considered her, and her mother, as friends, and I have no doubt that he would have protected either or both of them if the need arose. And no, I do NOT believe that he would have done it out of fear of, or lustful feelings for, Buffy. His affection for Dawn was something completely separate from anything that he felt for Buffy.