Tell Him, Show Him, I Don't Care (джен)

"John, what do you usually get your mum for Christmas?"
"I usually just sit by her grave and have a bit of a cry."
"What?"
"What?"
After a moment of awkward silence, John mumbles an incoherent excuse about his laundry and flees to his room.
It's Sherlock meeting John's family, yes. But with a little twist.