This is so lovely - warm and comforting. I really enjoyed the conversations at the Three Broomsticks between them; they showed a really deft hand with the dialogue that brought the characters to life. But I think this is my favorite bit of writing:
Harry immediately sprang up to protest but, his legs unsteady, he stumbled and ended up in a pair of deceptively strong arms. Blinking to clear the dizziness, he straightened up and found himself inches away from Severus' slightly exasperated face.
“How on earth have you managed to survive all these years?”
Harry grinned. “I've always had you there to catch me.”