Ada is right, poor Harry. But on the other side - what must have happened in his life, that Severus would rather live his life in his books than face the world outside.
I hope that Harry will be there to show Severus that there is something worthwile in the real world.
And I hope those two will be able to live a life together that will surpass any book ever written - because it would be life itself, not fiction.
(Isn't it strange to think in such way about fictional characters?)