Oh, children! How lovely, and awful, and delightfully terrible this is! I love the hues you've painted this -- Harry's desperation, the doomed love between Lily and Sevs, and the way Severus keeps staring at Harry once he finally puts it all together.
And I love that they're still 'alive' in his mind now. His own personal dementors, only they're not stealing joy, but loneliness.