(This is extremely self indulgent!)
Sirius knew that he lived a fairly good life, even if he had arses for parents and a little brother who was loyal to them for an inexplicable reason. He hated his parents but knew that there could be worse situations, like all the men currently being sent to fight their lives away.
Sirius would have had to enlist but his parents had shipped him off to the coast of France before that could happen. Their only excuse was so that he made sure Regulus didn't get caught up in everything. Their perfectly innocent son.
Sirius's daily routine usually consisted of reading the war updates, listening to the gramaphone or radio updates, and checking in with Regulus. He couldn't complain, especially as the death toll counted up. Or as the sound of distant planes travelled through the air.
But, of course, nothing could ever stay peaceful. It was a fairly warm afternoon and Sirius had been lounging in his sitting room, bored out of his mind. Until the crash. He stood up immediately and went to grab the old rifle Sirius had found one day while exploring.
He told Regulus to stay behind before venturing outside. It didn't take a long walk to see the plumes of smoke and bent out of shape metal. A plane had gone down. As Sirius got closer, he could see it was one of the British planes.
Something that Sirius didn't want to identify made him continue onwards, despite the high chance that the pilot was long dead. And yet, when he got next to the cockpit, the pilot was definitely still breathing.
An even more irrational decision brought Sirius to rescue the man back to the house. This was where he was now, in one of the washrooms. He carefully cleaned the easiest wounds when he noticed the pilot waking, cocking his head slightly, "don't punch me?"