Whatever the cause, Sherlock's in a coma and has been for a few days or weeks or whatever so that the chance he wakes up is getting smaller and the docs start getting sceptical... I'd like to see how Mycroft deals (or doesn't deal) with the increasing likelihood that he's going to lose his little brother, one of the few people who's not a goldfish in the fishbowl that is Mycroft's life.
But of course Sherlock wakes up, not to John, but to Mycroft sitting by his bedside. Maybe he's glad to see his big brother too?
No holmescest, just brotherly love. And adultverse please.