A/N - Edited slightly from the original. I put it all in one chapter because it flowed better that way.
Mycroft quietly considered his brandy. At least, he pretended to consider his brandy. He was more preoccupied with the newspaper on the table, its bold headline still screaming about the death of his brother, the fake genius, even after three months. His hand shook and he set the brandy down.
He had never been on good terms with his brother, but that didn't mean he didn't care for him. If Moriarty hadn't killed himself that day on the rooftop, Mycroft would have made him wish he had. He wanted to destroy the tabloids; threaten them so they never spat out those lies about his little brother again. But that was impossible. Not even Mycroft Holmes, who stopped world war three from erupting nearly every day before breakfast, could control the disgusting mass of vultures that was the media.
Mycroft sighed and drained his brandy. He needed to leave. Sitting in a quiet room gave him too much time to linger on things he'd much rather forget. Like how he'd sold out his own brother to an insane master criminal and gained nothing in return. Mummy would be very angry with him, if she were still here.
"Mycroft," she whispered, lungs weak from the cancer that gripped them. "Mycroft, come sit with mummy." A seventeen-year-old Mycroft perched on the edge of the hospital bed. His little brother had gone home with nanny. Mummy had been happy and smiling then, but now she seemed tired and resigned. He took her hand in his.
"Mycroft," she said. "Such a big boy. Your father would be proud." She coughed.
"Thank you, mother," whispered Mycroft.
"I want you to promise me something."
"Anything, mother."
"You are destined for big things, Mycroft Holmes." A few more racking coughs. "Your brother's future is less certain." Her thin hand gripped his with sudden strength.
"Look after your brother, Mycroft." Her breath wheezed and rattled. "Promise me. Promise that you will look after little Sherlock when I'm gone."
"I promise, mummy. I promise I'll look after him."
The pen flowed smoothly across the stationery, pouring the words of Mycroft's silent heart onto paper. He knew it really was too late for this and that it was absolute utter nonsense, but it would make him feel better. At least that's what he told himself.
The cemetery was quiet. Mycroft walked past the old and faded headstones, seeing but not registering the names of those who had once lived and breathed and loved and were now buried beneath the ground. He walked and walked until he came to the dark granite headstone under the tree. There was no epitaph; John, Lestrade, Mrs Hudson, Molly and himself had decided that it was not needed.
Mycroft stood there for a while, staring at nothing, before gently placing his offering against the cold black granite. It was too little, too late; things he should have told Sherlock a long time ago. It was all he had to offer the ghost of his little brother: an apology. Regret, honesty and worry. Anger and sadness. Guilt, hope and last wishes.
All he had to give was a letter. A note to his little brother.
Because that's what people do, isn't it?
They leave a note.
