[Sherlock ignores John's confusion--he was used to it when he often spouted some random deduction that was twenty steps ahead of everyone else--and instead focused on what he said about Mary. The detective's brows furrowed and he looked actually sympathetic. With all that poor John's been through, at least the stuff that he knew about--who knew what he went through here...yeah, he was experiencing some actual empathy.]

I'm...sorry to hear that.

[It's actually genuine, too.]

[Sherlock busied himself with the coffee, having absolutely no idea how to navigate socially unfamiliar situations, such as this one. All he did know was that John was probably lonely, and how awful that was. Right, maybe he should switch the topic before he came.]

So...changing the subject a bit, I can only assume you have so-called 'superpowers' as well?