A/N: I'm procrastinating, I have a paper and a handful of projects to do, but because I am the person that I am, I've decided to use this time to write this. I don't know how many of these there will be, but they're my headcanon behind Mycroft's quotes. Characters don't belong to me.
"All lives end. All hearts are broken. Caring is not an advantage."
"I'll never leave you." But he had, hadn't he? He'd made promises when it hadn't been his place to do so, and he had left a trail of broken hearts in his wake. Not just Mycroft's, but Sherlock's as well. As for their mother...well, Mycroft was sure that the news had found a way into her heart as well. If she had one.
"You'll take care of Sherlock." It had been a statement, not a question, leading Mycroft to believe that he hadn't a choice. But he had sworn to do so, nonetheless, no matter how difficult the task was proving to be. No matter how hard he tried, Mycroft was simply not an adult. He was seventeen, Sherlock was ten; their mother nearly out of her mind and their father newly buried. What a family they had made.
The boys had matured faster than they would have preferred; fending for themselves had forced them to do so. Life had been difficult to say the least, but it had made Mycroft into the man that he was today. Strong. Impassive. In control. At least on the surface. As Sherlock had grown older, he had become that way as well. Mycroft had quite hoped for the opposite, but it was no matter now: once Sherlock became set, it was hopeless to try and change him. Mycroft supposed that he'd had something to do with it. He had shut down completely, and Sherlock had learned behaviour by example.
"My, why does it hurt so much?" He hadn't had an answer prepared for such a question. There was so much that he could have said: Because we loved him, because he cared for us, because you have a heart. Instead, he had taken his younger brother firmly by the shoulders, and met his eyes.
"All lives end," he'd said gently, "All hearts are broken. Caring is not an advantage, Sherlock." He'd simply been trying to save his brother the pain.