He wanted him on the full moons, when Moony stole his mind and his humanity and he had no one to keep him sane and remind him who he was. He wanted him after, when he was ill and alone.

Knowing he was somewhere was something, but Remus couldn't pretend it was enough.
Oh, Remus. I wasn't a big fan of Sirius, but I felt bad for everyone he left behind. This is a nice look at grief and moving on.