Sherlock moves slowly back towards the door, blanket wrapped around him like a shawl. The kettle can wait a bloody minute.
He opens the door to his brother. His much-younger-than-the-last-time-he-saw-him brother. His brother who has just clearly come from some kind of ordeal that is none too pleasant. But it is his brother, and no matter what Sherlock has said and done in the past, no matter the words that may have somehow slipped from him, he loves Mycroft a ridiculous amount.
But they both seem a little too delicate for a passionate brotherly embrace.
Sherlock steps aside without a word, letting him in.
"The kettle's just boiled," he says, his way of greeting. "Or do you perhaps need something stronger, brother?"