It's okay, Mycroft wants to say, and it is distinctly unnerving. He has never found himself wishing to provide comfort for someone - someone other than Sherlock, at any rate, or occasionally their parents - and yet, today, he rather finds that he does.
Usually, grief leaves him unmoved. Death happens, the necessary counterpart to life, and, whilst he would not particularly wish it upon anyone, he fails to see the requirement for sobbing and sighing.
John, on the other hand, could make a living out of grieving, and Mycroft finds it distasteful, discomforting, and something he would actually choose to prevent, if he could.
Marylebone Road. I shall see you at seven, he texts (root canal, again; for some reason, no amount of preventative action seems enough to keep his teeth in passable condition), signing it MH, as always, and hits send.
John Watson will be there, he knows, even if sentimentality requires that he will not enter the building in which he lived with Sherlock. He will be there, because Mycroft is the only link to Sherlock John has.
It's okay, he wants to say. He's not dead.
He will not, because revealing the truth will have few benefits and cause no little amount of harm. All of Sherlock's actions to disband Moriarty's operations will be undermined, and the lives of those most dear to his brother will be in danger again, the same danger Sherlock sought to save them from months ago. No good will come of it.
No good will come of it at all, because John will not believe him. Mycroft should have anticipated there being a downside to involving John Watson in his plan to spare Sherlock the pain of Ms Adler's demise, and in this the downside becomes most apparent; John is already well aware of his propensity towards necessary dishonesty, and unless he sees the evidence of Sherlock's continued survival with his own eyes, he will not believe this is anything more than a lie.
He's not dead, he wishes to say, and although he will not, he will offer what little comfort he can.
Why? his phone replies, and Mycroft almost finds himself smiling. It seems John has gone beyond answering the whims of the Holmes brothers without question, and Mycroft feels oddly pleased about that.
Fish and chips, he types in return; it is what people do, or so he's heard, and whilst he will not betray Sherlock's confidences and the mission, he will do what he can.
Sure enough, seven arrives, and Dr John Watson is waiting for him.