Hey, alysscarlet! Just a quick comment to clarify something I should have been more clear about. In "The Final Problem," it's Moriarty who arranges to have a message sent to Watson about a sick English woman back at their hotel. I'm not actually sure if it was Sherlock who sent the false message to John in "The Reichenbach Fall". I just figured it might be as I assumed he would have more reason to want John out of the way as he orchestrated the meeting with Moriarty. If anything, I'm guessing Moriarty would want John there so that he could actually hold him hostage directly in front of Sherlock.

I can understand why you're having a hard time picturing Sherlock with a heart. However, if there's one person in the world that he cares about it's John. This is shown in canon, and I would argue that it's shown in Sherlock as well. Canon Holmes was actually willing to sacrifice himself in "The Final Problem" to rid the world of Moriarty. I'm pretty sure Sherlock isn't that selfless, but I don't have a problem seeing him lay down his life for John.