If there was one thing in this world that Sirius Black was not, it was a coward.
I imagine he was quite panicked when he found out what Harry had done. We all were. I can see him, tearing down the stairs and fastening his cloak, wand in his teeth, for once not at all worried about waking his mother's portrait. I would like to think he hesitated before throwing open the door and stepping outside and apparating to the ministry, but I've known him far too long and far too well to even consider the possibility that something so sensible would have crossed his mind.
Therefore, it wasn't at all a shock to me when he sprinted up to us, panting, anxious to know where his godson was. I didn't scold him for disobeying Dumbledore's orders and leaving Grimmauld Place. He was never one to stand down and let others fight without him when his friends needed his help. We searched the Department of Mysteries in uneasy silence, praying that the worst-case scenarios playing out in our minds would remain there. In hindsight, there is so much I wish I had said to him, about just how much his friendship really meant to me.
We found them making quite a stand against the Death Eaters. I remember joining the fray, but the battle that followed remains a blur. However, clearly I remember watching him battle Bella Lestrange. Never will I forget his challenge, "You can do better than that!" spoken moments before her spell hit him square in the chest. Never will I forget how the laughter still lingered on his face as he fell backwards through the veil, how I held Harry back so he wouldn't follow his godfather, and how I crushed a boy's heart, and my own, when I said the person they loved most in this world was gone.
Yes, if there was one thing in this world that Sirius Black was not, it was a coward. In these dark times, in that alone, I find strength.