Not my characters.
Sherlock managed to wash out most of the blood, a small amount of it real and the rest of it hastily concocted from ingredients found in the labs at Bart's, before wrapping himself in Mycroft's dressing gown and collapsing in the hidden basement guest room. The one Mycroft always kept tidy for his brother, where Sherlock had been kept safe (despite numerous complaints) while detoxing from cocaine and God-knows-what had been mixed in with his dealer's doses. Sherlock had escaped twice only to wake up back there, though naturally allowed to leave once the private doctor and therapist both pronounced him clean, and that he willingly returned now, years later, spoke volumes.
They had been simpler times, Mycroft thought as he sat by the bed, still fully suited though with a loosened tie, his chin in his hands. He'd managed to retrieve Sherlock's violin from grieving John, claiming sentimental value, and Sherlock would find it on the bedside table when he woke.
Father died when Mycroft was nine and Sherlock was two. His last words to Mycroft were, "Take care of you brother." It was almost a cliche, really. But Mummy had always been - continued to be - affectionate towards both of them in a more abstract way, always busy with her campaigns, her socials, her philanthropy, her discreet and careful workings of politics. It was from her that Mycroft had learned how to turn a minor government position into running the world behind the scenes.
It was Father who had given him his one weakness. As Sherlock had been foisted upon nursemaids and nannies, Mycroft had inspected them and their backgrounds, dismissing the ones inadequate. And they came and went at such a constant rate, unable to endure Sherlock dissecting small animals (already dead, he'd protest), announcing their private love affairs for all to hear in caustic innocence, the tantrums, the periods of silence, the wavering and finicky appetite - at such a rate that it was Mycroft who was a constant caretaker and parental figure in Sherlock's life.
Mycroft told no one that when he kept a small window on his browser, late at night, open to footage of Sherlock sleeping (or stubbornly doing anything but sleeping, fueled by coffee and nervous energy), he wished he could tuck his little brother into bed and read him medical case files and passages from Herodotus, then kiss his eyelids as they closed. He wished now that he could cling to him and apologize for everything, everything. In trying to reduce Moriarty's threat to the world - and consequently to Sherlock - he'd been manipulated into nearly destroying him.
It was no advantage. It was never an advantage.
Mycroft brushed a lock of hair out of Sherlock's face. And sat. And watched. And wished.