Parts of souls do not go on alone. When Voldemort returns to a body he is much more sane than before and realizes that he cannot go on as he started. Finding some old laws he sets out to reach his goals in another way. Harry will find his world turned upside down once more and we will see how people react when the evil is not acting how they think it should.

He didn't know which was worse. A potion induced waking-nightmareor he was five years old again. Now what? Did he do what Dumbledore wanted or was he going to be his own man, again?

Always Protector does just that, it protects from anything and everything that the caster thinks of as a danger at any time, no matter what. Severus cast it on the Potter family, but it could only protect one. This is a Snape rescues Harry from the Dursleys tale.