Sherlock is sick and he hates it. Sherlock is sick and he's a terrible patient. Lucky, he is married to a good doctor and a good doctor who can take good care of him, no matter how much Sherlock bitches and whines.
He's been tucked up on the sofa whilst John takes more time out of their honeymoon and goes to visit the people at the hospital, or hunt down the people who were at the hospital to make sure they're all alive.
John is a good doctor.
It's windy outside, and it's dark because it's probably going to rain, but that doesn't mean that Sherlock can't see the movement of a person approaching over the sand.
He does a double take just to make sure, just to confirm that it is Mycroft. It's been a long time since he saw him. After that brief visit on the train after his last accident in...where was it now? Nevada? Or this might be a completely different Mycroft. He can't tell from this distance. But Sherlock pulls himself from his seat anyway, wraps the blanket around himself and goes to put the kettle on before his brother reaches the front door. Anyway, John'll be back soon.