Patience.

Snape survived but at a cost. Dumbledore had to work a lot of things out including how his owning the three deathly hallows allowed him to conquer death. Although the old man survived and is relatively healthy, Snape isn't the same. The man is more closed off and only lives because he knows Albus needs him to lean on. This is where Athena comes in as a sort of potions apprentice. Snape thinks Albus has lost his mind but in reality Snape needs the help as he struggles both physically and emotionally.

JKROWLING owns everything apart from the students as well as Athena and the mentioned friends.

I love HP and love all of the professors as well as the photos at the top of each chapter.