Aw, thank you so very much! Severus is a lovely puzzle. Did I ever say how revealing I found your piece on Severus' work? Of course it was pennance, and punishment and so much. I had never thought before about how much he had to do, but had only looked at each aspect in isolation. I'm trying to always remember to incorporate that idea into my writing. It rang so very true and was so illuminating.
I couldn't understand at first how he could do it at all (disregarding book 7 revelations.) But finally I realised that Voldemort seemed to be dead, the DeathEaters were dead or worse (save a few such as Lucius), and Severus must have been completely lost, as well as having been recently left to face what they had been doing alone, without encouragement or immediate familial feeling. He must have been desperate as well as repentant and horrified both by himself and what had happened to his friends (brothers.)