This is touching and poignant -- as usual. :-) I really like the bit of humour at the beginning with Sherlock trying to break into Lestrade's hotel room when he could have easily knocked. I love the conversation they have about the Baskerville case, Sherlock's reaction to the drug, and Lestrade's issue with Sherlock's "one friend" comment. In fact, that bit of dialogue around the friend issue is one of my favourite parts of the story:

“I do have only one friend.”

“Well, what’m I, then?” Lestrade said irritably. “And if you say ‘handler,’ I will punch you.”

“Oh, for God’s sake,” Sherlock snapped. “I didn’t mean it like that.”

He slipped out of his coat, draping it over the back of a chair before sitting down next to Lestrade on the bed.

“I have only the one friend,” he said slowly, enunciating each word as though he was speaking to a small child, “because you’re my partner.”