I can only imagine the intensity of Crowley's Courage...
When he defied both heaven and hell during the trials of Job, to stage his own personal rebellion. He was done with obedience to cruelty, on either side...
Saving the goats was a small (but still dangerous) defiance against so much senseless destruction. Disobedience in hell was not allowed. Free will was for humans, not for demons.
Revealing that act to an angel, even the kindest of angels, was a tremendous risk. (Angels always follow the rules, don't they?) It was an act of tremendous Courage.
Crowley was done. He was on his own side. But he was lonely. (Breaking away to do what you believe is right is often lonely.) And he liked this angel, who had a bit of defiant bastard in him, and his own loneliness.
So, step by step, test by test, Crowley gave his trust to Aziraphale, both challenging him and reaching out in acts of friendship...
[It's easy to forget that, sometimes, friendship itself is a courageous act. Especially when it challenges what's expected of you.]
...And ultimately protecting the children he was sent to destroy. Hell would intensely punish Crowley's disobedience if they found out that he'd saved them.
[Maybe they did. We don't know what happened next. We don't see him again until the Crucifixion.]
But Crowley's greatest act of courage risked his very existance... When he rushed into a room full of angels to stop their grieving mother from cursing God... an action considered the greatest human sin. It would have doomed her. The children would have no mother to return to.
