“[A person who is falling asleep] may find themselves shivering in their sleep, turning over in a really vulnerable way, or clutching themselves. [...] This is, of course, a cue for another character (say, Bob) to come along, see the sleeper (say, Alice) and react to it—by tenderly draping a blanket (or, in less providing situations, a coat) over her shoulders, petting her on the head, and saying, "Sleep tight, Alice.””
…Sherlock’s drug-induced flail about his room brings John in out of concern. He plops Sherlock back into bed and dutifully covers him with his sheet again, leaving the room with an “I’ll be next door if you need me.” The music choice for this scene makes what could be comic-relief undeniably tender - John will be there to take care of and watch over Sherlock no matter what, even if he says he doesn’t need him to. [ref x]